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	400 in 7.5 billion		2019-08-28
		From Emma: What is a better way to express 400 in 7.5 billion? My daughter has a rare condition, I want to know the answer to say “she is 1 in a ...” Answered by Penny Nom.
	The sum of three consecutive even integers		2019-01-27
		From Pauleen: Translate this into algebraic expression The sum of three consecutive even integers, if x is the first even integer Answered by Penny Nom.
	Solve for x in Y=1.5x + log (1+x)		2018-12-23
		From Asadollah: Please restate below expression in terms of y Y=1.5x + log (1+x) Thanks Answered by Penny Nom.
	Predicting the number of fish in a lake		2018-09-16
		From April: A researcher catches 30 fish in a pond, attaches a marker to their fin and releases them. The next day she places a large net in the water and catches 9 fish. 3 have the marker attached to their fin. Can she predict the number of fish in the pond??? Thank you Answered by Penny Nom.
	Pre tax and post tax percentages		2018-05-22
		From Tom: Hi, I work in a clothes shop which can also do mail-orders. My Head Office has sent a report with which we can check the records we keep in store tally with those at HO. According to that report we have taken £2578.25 in orders, excluding VAT (20%), which would therefore be £3093.91 including VAT (2578.25+20%=3093.91). According to my records, we have taken £3179.32 including VAT, which would be £2543.45 excluding VAT (3179.32-20%=2543.45). Why is it that the difference between the VAT inclusive figures (3179.32-3093.91) is +£85.41, but the difference between the VAT exclusive figures (2543.45-2578.26) is -£34.81? Now, I can see from the report that 1 order has not been recorded by HO, and I know that our average order value is around £30, so the -£34.81 makes sense. But surely both figures should be a minus, regardless of whether they include VAT? I'm sure there is an obvious answer, but I just cannot see it! Any help would be gratefully received. Thanks, Tom Answered by Penny Nom.
	Two expressions for the perimeter of a a rectangle		2018-05-13
		From Slayde: A rectangular house has one side 4 metres longer than the other. Create two different expressions for its perimeter. The expressions should be given in factorised and expanded form. Answered by Penny Nom.
	Simplify 1/2^i		2018-01-28
		From Deepak: How do I simplify this complex equation: z=1/(2^i) Answered by Penny Nom.
	y as an expression in terms of x		2018-01-20
		From Mark: What is y as an expression in terms of x ? Answered by pennt.
	8^3/2(2+2)		2017-01-13
		From Mary: 8^3/2(2+2) Answered by Penny Nom.
	The amount of material remaining on a roll		2016-11-11
		From Yoh: Question from Yoh: Hello, I am trying to find impressions on a roll (either full roll or partial). Let's say I have the following information. - Outer Diameter of roll - Inner Diameter of roll (cardboard core) - thickness per layer - Each cut off length (impression length) Now let's say a roll has a 40in outer diameter, the cardboard core has a 3.75in diameter and a thickness of .002. Each impression has a cut off of 14inches. With this the roll will have approximately 2,700 impressions. How would I find the remaining impressions if the outer diameter of the roll is only 6.5inches? Thank you. Answered by Penny Nom.
	A mixed number as a percent		2016-10-18
		From Jayda: how go you change a mixed number into a percent Ex. 3 3/4 Answered by Penny Nom.
	Compressed Earth blocks		2016-03-02
		From John: how many 14"x10"x4" blocks do I need for a 1300sq foot house 8 foot high Answered by Penny Nom.
	The uniqueness of the lub		2015-10-25
		From Aishwarya: Prove that if the lub and glb of a set exist then they are unique Answered by Penny Nom.
	Why is the area of square not conserved when it changes to a rhombus?		2015-06-28
		From shubham: Why is the area of square not conserved when it changes to a rhombus, both have equal sides still rhombus have less area than square.?? Answered by Penny Nom.
	1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 x 0 + 1 = ?		2015-06-18
		From Sharon: 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 x 0 + 1 = ? I got 1 as my answer despite BODMAS making it 12 because logic tells me I ought to place brackets around the first set of repeated addition. Could you please clarify this for me? Thank you 😊 Answered by Harley Weston.
	An angle of depression problem		2015-05-14
		From haxir: find the height of the balloon directly above a town if the measure of angle of depression of another town 5km from the first town is 20°!6` Answered by Penny Nom.
	Angles of elevation and depression		2015-03-08
		From Timmy: Joel is walking down a street and sees a 115 ft tall building in front of him. He stops 190 feet from the base of the building at the tip of the building's shadow. Round answers to three decimal places. A. If there was a piece of rope from the top of the building to Joel, how long would it be? B. What is the angle of elevation from Joel to the top of the building? C. Margaret says that she could find the angle of depression from the top of the building to Joel by subtracting the angle of elevation from 90°. Is she correct? Explain. Answered by Penny Nom.
	A man is standing on top of a building		2015-03-06
		From kiki: a man of height 1.5m standing on top of a building of height 48.5m views another building across the square. he observe that the angle of depression of the bottom of the building is 40 degrees and the angle of depression of the top of the building is 5 degrees. Both buildings stand on the same level a) calculate the distance of the man from the base of the building across the square measured along the line of sight Answered by Penny Nom.
	3 over "x" plus 5		2015-02-23
		From Kenny: 3 over "x" plus 5. I don't know this is either a polynomial and if so how would you define it. Answered by Harley Weston.
	128/(-16)/(-2)		2015-01-28
		From jackie: 128/(-16)/(-2) I was wondering if you can show me how to work this question out Answered by Harley Weston.
	The height of a building		2015-01-20
		From Emily: A man 2m high observes the angle of elevation to the top of the building to be 70 degrees. And the angle of depression to the bottom of the building to be 19 degrees. How tall is the building? Answered by Robert Dawson.
	What is 20 and 3/5 of 10?		2014-11-26
		From Jeannine: What is 20 and 3/5 of 10? Question is written exactly this way. Is this 20 3/5 times 10 (103/5 times 10), or is it 20 and (3/5 times 10)? Answered by Penny Nom.
	Pre algebra		2014-10-12
		From mohamed: i want to know the meaning of pre algebra Answered by Penny Nom.
	The angle of depression		2014-03-08
		From Ranger_minor: A woman of height 1.4 metres standing on the top of a building 34.6 metres high views a tree some distance away. she observes that the angle of depression of the bottom of the tree is 35 degrees and the angle of depression of the top of the tree is 29 degrees. assume that the building and the tree are on level ground : 1). calculate the distance of the woman from the top of the tree measured along her line of sight. Answered by Penny Nom.
	Using trig to find the height of a hill		2013-08-14
		From Anna: From the top of a hill, the angles of depression of two successive milestones on a level road, which leads straight away from the hill, are 5degrees and 15degrees respectively. Fine the height of the hill. Suggestion: BE is drawn perpendicular to AD. Find BE, then BD, finally CD. Thanks :) Answered by Penny Nom.
	Bags of pre-mixed concrete		2013-04-12
		From Bruce: Hello there, I need two cubic yards of concrete for a playgound I am installing for my kids. That much i have figured out. I am stumped over the number of 25kg bags of pre-mixed concrete i will need to accomplish my goal. Your help would be greatly appreciated. Thanks Bruce Answered by Harley Weston.
	An algebraic exercise		2013-03-18
		From autumn: given: f(x)=x/(x^2+2) determine: [f(x-h)-f(x)]/h Answered by Penny Nom.
	A messy arithmetic expression		2013-02-24
		From niiaryee: (((((5^2*4^3)1/5+9^3/3)+(25+(4*5)/15)^2-10)/10/2)3))))) Answered by Penny Nom.
	The angles of elevation and depression		2012-12-03
		From Chelsey: a person on a balcony of one building looks towards a second building. if the angle of elevation to the top of the second building is 25 degrees, the angle of depression to the bottom of the second building is 17 degrees, and the balcony of the first building is 22 feet above the ground, what is the height of the second building? Answered by Penny Nom.
	A mathematical expression with the answer 7		2012-11-10
		From emily: hey um i need to find and problem that fallows bedmas that has one division one multiplication and one sub and one add and one brackets and one exponents that has the answer of number 7 Answered by Penny Nom.
	Forming an algebraic expression		2012-10-27
		From ashley: A sidewalk has a constant width W and comprises several short sections having lengths 12, 14,and 10 feet. How do I find the simplified expression that gives the number of square feet of sidewalk? Answered by Penny Nom.
	Find an algebraic expression		2012-10-03
		From Karen: Question from Karen, a parent: Find an algebraic expression relating the input and output. input output     3 1 9 3 15 5 21 7 27 9 Answered by Penny Nom.
	The spread of a rumor		2012-04-09
		From Roohi: The function f(t) = a/(1+3e^(-bt)) has also been used to model the spread of a rumor. Suppose that a= 70 and b=3 0.2. Compute f(2), the percentage of the population that has heard the rumor after 2 hours. Compute f'(2) and describe what it represents. Compute lim t approaches infinity and describe what it represents. Answered by Penny Nom.
	An arithmetic expression		2011-11-28
		From Muhmmad: 2/5*-3/7-1/6*3/2+1/14*2/5 Answered by Penny Nom.
	The value after 30 years		2010-12-15
		From Abeth: At the end of every year, the owners of a building which costs 2, 500, 000 pesos deducts 15% from its carrying value as estimated at the beginning of the year. find the estimated value at the end of 30 years. Answered by Penny Nom.
	How many cubic metres of water can safely be stored in the tank?		2010-09-10
		From susanna: This water tank is a perfect sphere with an inner radius of 12 metres. However, they used inferior materials to build the water tank, and the tank can only withstand a water pressure of 185 kiloPascals. Assume the density of water is exactly 1000 kg/m3, gravity is 9.8 metres/s2, and disregard atmospheric pressure. How many cubic metres of water can safely be stored in the tank? Round DOWN to the nearest whole number (since rounding up could be catastrophic in this instance!), and please submit only a number with no other information. Answered by Robert Dawson.
	Four less than three times a number is 14		2010-04-16
		From David: My daughter has two questions that we could use some help with. First ? Four less than three times a number is 14 Secound? The quotient of -15 and w Answered by Penny Nom.
	Metric prefixes		2010-03-16
		From ali: How do you convert zectometres to yoctometres Answered by Robert Dawson.
	Eye Height Level Found from Visual Angle		2009-08-07
		From Jolie: Hello, I am trying to figure out what height from the ground a person's eyes are if they have a 12 degree visual angle to a screen that is 58cm away from their eyes? Thank you. Answered by Janice Cotcher.
	Pre-Algebra Resources		2009-07-16
		From M: What is the best pre algebra book that is inexpensive and will really help me to understand pre algebra? Answered by Janice Cotcher.
	x^3+1/x^3=18*sqrt(3)		2009-07-08
		From Nazrul: If x^3+1/x^3=18*sqrt(3) then how can I evaluate the value of x+1/x? Thank you for your help. Answered by Robert Dawson.
	Finding Force When Pressure and Area Are Known		2009-06-25
		From chris: i need to calculate the force for a tube. given the follwing data. pressure is 900 PSI Tube is 6 m long by 1.5m Outside Diameter Answered by Janice Cotcher.
	Pressure at Given Depth		2009-02-22
		From Tamara: A sea is 3km deep. The average density of sea water there is 1020 kg/m^3. What is the water pressure at the bottom? Answered by Janice Cotcher.
	Angle of depression		2009-02-18
		From Meeka: An aircraft flying at an altitude of 2000m is approaching an airport. If the angle of depression of the airport is 5 degrees, what is the distance from the plane to the airport measured along the ground? Round your answer to the nearest tenth of a kilometer. Answered by Robert Dawson.
	The whole number that precedes a number w+3		2009-01-17
		From Morgan: write a variable expression for "The whole number that precedes a number w+3" Answered by Penny Nom.
	An expression for q quarters and n nickles		2009-01-16
		From Morgan: a variable expression for: "The value in cents of q quarters and n nickels" Answered by Penny Nom.
	Algebraic fractions		2008-10-06
		From Kayla: (x^2-9)/x times (x^3-4x)/(x^2+5x+6) Answered by Harley Weston.
	A security camera		2008-09-07
		From Rita: A security camera in a neighborhhod carnival is mounted on a wall 9 feet above the floor inside a video gallery. What angle of depression should be used if the camera is to be directed to a spot 6 feet above the floor and 12 feet from the wall? Answered by Stephen La Rocque and Harley Weston.
	An algebraic expression		2008-08-29
		From Antonio: write a variable expression for 9 less than k Answered by Penny Nom.
	The square root of a fraction		2008-08-24
		From Lauren: How do you solve square roots of fractions? Does the format change if it is either a proper or an improper fraction? Ex. the square root of 1/4 or the square roots of 80/25 Answered by Penny Nom.
	How many decimeters are in a meter?		2008-08-11
		From Julia: How many decimeters are in a meter? Answered by Penny Nom.
	Express as a function of x		2008-07-14
		From Rita: Express the area A of an isosceles right triangle as a function of x of one of the two equal sides. NOTE: I always see the phrase "Express as a function of x" in math textbooks. What exactly does that phrase mean? I also have seen it written as "Express in terms of x." Answered by Penny Nom.
	1/3-5/6=1/x, solve for x		2008-05-01
		From Lavada: 1/3-5/6=1/x How do I solve this problem. Answered by Penny Nom.
	Simplify 5x^5/8 / 15x^2/12		2008-04-18
		From Kyler: 5x^5/8 / 15x^2/12 Divide the rational expressions. Simplify the results. Answered by Penny Nom.
	How would I graph: x - 2 divided by x^2 - 4?		2008-03-19
		From Sean: How would I graph: x - 2 divided by x^2 - 4 using a method in extreme values of functions or completing the square x - 2/ x^2-4 Answered by Stephen La Rocque.
	An arithmetic expression		2008-03-05
		From Kasani: evaluate the expression: -2^-1[-14 - 4(-6)] - (7 - 3) Answered by Penny Nom.
	How do I convert mcg to ml?		2008-01-27
		From David: How do I convert mcg to ml? Answered by Stephen La Rocque.
	Simplifying square roots		2007-12-19
		From Ciara: How would you calculate 2 to the square root of 8 plus 4 to the square root of 2 minus 5 to the square root of 2? Answered by Stephen La Rocque.
	Imprecise measurements		2007-12-09
		From Sara: Hi! A water tank, in the shape of a cuboid (length 1.6 m, height 1.2 m, breadth 0.8 m), is full of water. Water is drained from the tank at a rate of 8 litres per minute. The dimensions of the tank are given to the nearest 10 cm. The rate at which the water is drained from the tank is given to the nearest 0.5 litres per minute. (a) Calculate the smallest possible time to drain the tank. (b) Calculate the greatest possible time to drain the tank. Many thanks!!! Answered by Stephen La Rocque.
	Order of operations		2007-10-17
		From Devon: What function precedes the other? ie; 18 - 4 x2 = Answered by Penny Nom.
	Subtracting rational expressions		2007-10-09
		From Pamela: Subtract: 6p – w __ 4c + p w – 4 w – 4 Answered by Stephen La Rocque.
	Variable expressions - part 2		2007-09-04
		From lisa: how do I write a variable expression for word phrase example x less than = 2 or 2 less than p 4 fewer than job please help Answered by Penny Nom.
	Variable expressions		2007-09-04
		From Eric: how so i write a numerical or variable expression for each quantity. example two dozen eggs or d dozen eggs number of quarts ub a 3 gallons Answered by Penny Nom.
	The quotient of thirty and ten times a number.		2007-09-02
		From Jenna: I need help on How to translate a phrase into an algebraic expression: The quotient of thirty and ten times a number. Answered by Penny Nom.
	george, thomas, abe, alexander...		2007-09-01
		From lori: george, thomas, abe, alexander... come up with the next few im confused and need help!! Answered by Stephen la Rocque and Harley Weston.
	Angle of depression to a football		2007-08-15
		From Tosin: The angle of depression to a football from the top of building 10m high is 17 degrees. Find the distance of the ball from the foot of the building. Answered by Stephen La Rocque.
	Angle of depression		2007-07-23
		From joyce: hello, here is my problem...... As you stand on a bridge w/c is 100 ft. above the water you are looking @ an approaching barge. If the A of top of the front of the bridge is 29.04 degrees and the angle of depression of the rear is 17.36 degrees . Find the length of the barge? Answered by Harley Weston.
	Angle of depression (declination) between sailboat observations		2007-07-18
		From Joyce: From a cliff 150 ft above a lake, we see a boat sailing directly towards us. The angle of depression of the boat is seen to be 5 degrees and 7 inches and 11 degrees and 18 inches. Find the distance sailed between observations. Answered by Stephen La Rocque.
	The two towers (angles of elevation trigonometry)		2007-07-14
		From joyce: The angle of elevation of tower B from the top of tower A is 28 degrees and the angle of elevation of the top of tower A from the base is 46 degrees Find the height of tower A if tower B is 120 m high? Answered by Stephen La Rocque.
	Simplifying a quartic rational expression using long division		2007-06-14
		From Megan: x+2/12x^4+17x^3+0x^2+8x-40= Answered by Stephen La Rocque and Penny Nom.
	Angles of depression		2007-06-13
		From Phonda: The pilot of a small private plane can look forward and see the control tower for a small airstrip. Beyond that is a large factory that is 3 milies from the airstrip. The angles of depression are 12.5 degrees and 4.8 degrees respectively. Find the airplane's altitude, to the nearest ten feet. Answered by Stephen La Rocque.
	Express a certain variable as a function of another variable		2007-06-12
		From Gilligan: The volume V of a right circular cone is V = (1/3)pi(r^2)(h). If the height is TWICE the radius, express the volume V as a function of r. I see the phrase "express a certain variable as a function of another variable" a lot in math books. What exactly does that mean? Is there another way to say the same thing? Answered by Stephen La Rocque.
	Rational polynomial expressions		2007-06-09
		From a student: I have a question that continues to lead me to the answer x/(x - 1) but according to my math book, the answer should be 1/(x - 1). Who is right? Who is wrong? Here is the question: (x^2 - 6x - 27)/(x^2 - 11x + 18) DIVIDED by (x^3 + 2x^2 - 3x)/(x^2 - 2x) Answered by Stephen La Rocque.
	A pipe full of water		2007-06-07
		From paul: What is the volume of water in a 100mm inside diameter pipe that is 12.5 meters long What would be the pressure at the bottom if the pipe was installed in the vertical plain Answered by Steve La Rocque, Penny Nom and Gabriel Potter.
	A machine depreciates by 20% each year		2007-06-03
		From katie: the value of a machine depreciates by 20% each year. How would i find what single decimal number to multiple the original value by to find its value after 2 years? Answered by Penny Nom.
	Angle of Elevation		2007-05-10
		From Micky: Two Buildings are on opposite sides of a street 40 feet wide. The taller of the two buildings is 580 feet tall. The angle of depression from the top of the tallest building to the shorter building across the street is 57 degrees. Find the height of the shorter building. Answered by Stephen La Rocque.
	Pre-algebra volume of a prism		2007-05-10
		From Brenda: Find the volume of a triangular prism with a base of 5 cm by 5 cm and a height of 12.5 cm. Round to the nearest tenth. Answered by Stephen La Rocque.
	Converting from mm to cm		2007-05-08
		From Amanda: How do you convert mm into centimeters? Answered by Gabriel Potter and Steve La Rocque.
	Simplifying a rational expression		2007-04-29
		From Tamika: X^2 + 10X + 24 ______________ X + 6 SIMPLIFY EACH RATIONAL EXPRESSION (IF YOU CAN'T SIMPLIFY IT, WRITE ALREADY SIMPLIFIED) Answered by Stephen La Rocque.
	The angle of depression		2007-04-14
		From Mary-Beth: Two towers are 30 m apart. From the 15th floor, 40 m up, find the angle of depression to the base of the taller tower? I think the answer is 53, but the answer book says 37. Answered by Penny Nom.
	Adding and Subtracting Rational Expressions		2007-03-21
		From Pricilla: Pricilla I do not know how to do this problem. Don't know where to start. [(5)/(2x-8)]+[(3x^2+15)/(x^3-4x^2+5x-20)] Answered by Stephen La Rocque.
	Angles of depression		2007-03-21
		From romaine: a woman of height 1.4m standing on top of a building of height 34.6m veiws a tree some distance away. she observes that the angle of depression of the bottom of the tree is 35 degrees, and the angle of depression of the top of the tree is 29 degrees. assume that the building and the tree is on level ground. (a) calculate the distance of the woman from the top of the tree measured along her line of sight. (b) determine the height of the tree. Answered by Stephen La Rocque.
	Simplifying exprressions		2006-11-06
		From Jessica: -21(a+2b)+14a-9b Answered by Stephen La Rocque.
	The real numbers with decimal representations consisting of all 1s.		2006-10-29
		From Ivessa: Determine if the following set is countable or uncountable : the real numbers with decimal representations consisting of all 1s. Answered by Steve La Rocque and Walter Whiteley.
	How do you write a variable expression		2006-10-11
		From Josh: How do you write a variable expression for the following: The amount of money Waldo has if he has $10 more than Joe and How much weight Kirk can lift if he lifts 30 lbs more than his brother. Answered by Stephen La Rocque.
	Metric Conversions		2006-09-02
		From Patricia: I have a new difficulty, metric conversion when it involves the prefixes. Some problems I need help with are: Answered by Stephen La Rocque.
	My wife's recent pregnancy,		2006-07-24
		From Tom: During my wife's recent pregnancy, it so happened that my wife's 29th birthday fell on the exact same day that her unborn child was 29 weeks old (i.e. it was 29 x 7 days from the date of conception as advised by the doctor) I would like to know what the probability is of the above event occurring for a randomly chosen pregnant woman i.e. that the pregnant mum's x'th birthday falls on the same day that the unborn child is x weeks old EXACTLY. Answered by Stephen La Rocque.
	Simplify the variable expression: 3g^2h over 12gh		2006-02-09
		From Andrew: okay the question says simplify the variable expression: 3g2h over 12gh how would u do this? Answered by Penny Nom.
	preuve par neuf		2006-02-08
		From Thonet: Je suis enseignante en primaire en Belgique et j'aii actuellement une stagiaire étudiante qui va devoir apprendre à mes élèves comment fonctionne la preuve par 9. Elle sait expliciter concrètement celle-ci et a trouvé l'explication du pourquoi de sa fonction mais nous ne savons pas l'origine de cette application mathématique... Qui l'a inventée ? Pourquoi ? ... Pourriez-vous nous éclairer ? Answered by Claude Tardif.
	Rational expressions		2005-11-15
		From Zach: I can solve easy problems such as (x/2)+3=2+(3x/4). That is easy because the Lowest Common Denominator is 4. But what really gets me stuck is a problem like this one. (6/x-2) = ( 21/(x-2)(x+2) )+ 1. Answered by Penny Nom.
	Coefficients, constants and like terms		2005-10-05
		From Elizabeth: In the equation -8y+6ab+7-3ab what are the coefficients; the like terms and constants? Answered by Penny.
	2x/x^2-9 - 6/x^2+x-12		2005-09-27
		From Emily Ann: 2x/x2-9 - 6/x2+x-12 Answered by Penny Nom.
	A rational arithmetic expression		2005-09-14
		From Vijay: How to simplify following Grade 9 math problem: (4/-9) X (-21/-32) X (-3/14) Answered by Penny Nom.
	Rational expressions		2004-09-24
		From A student: In general, I understand rational expressions except when it comes to solving problems such as: x+y/2x-y - 2x/y-2x or m-4/3m-4 + 3m+2/4-3m I am confounded by the issue of having to find a common denominator. For example, if I tried to solve these problems by multiplying both denominators they would still be uncommon. Answered by Claude Tardif.
	An equation with rational terms		2004-06-17
		From Louise: simplify the expression (a2+n2)/2n = a2 + (a2-n2)/2n Answered by Penny Nom.
	Angles of elevation and depression		2004-05-18
		From Anjum: what is the difference between an angle of elevation and angle of depression? Answered by Penny Nom.
	Rational expressions		2004-04-06
		From Shivani: I am in 11th grade Honors Algebra II. We are currently learning about adding and subtracting rational expressions. I looked at the other questions that were similar to that of mine, but they weren't quite answering my question. I have been working on many problems to practice and see if I can come up with the correct answer, but I can't, I got like 2 out of every 7 right on my school homework. I get the easy ones, where when you have to find the LCD, it's just the other denominator. But, on others you have to really think about it. Those are hard. Here are some of the problems that I cannot get at all: (x2 - 3x + 1)/(x2 - 4) - (x2 + 2x +4)/(2 - x) - (x - 4) /(x - 2) The correct answer is: (x3 + 4x2 + 7x + 17)/(x2 - 4) Answered by Penny Nom.
	A metric prefix table		2004-03-07
		From April: Can you tell me what the scale is for nano, micro, mega, kilo, etc.... I know that mega is 10 to the sixth power but I can't remember the other ones. Answered by Penny Nom.
	Rearranging an expression		2004-02-24
		From Corey: use the following formula to answer the question F=9c divided by 5 plus 32 rearange the formula to solve for c how many degrees fahrenheit would it be it it was: 0 degrees celcius -10 degrees celcius -46 degrees celcius Answered by Penny Nom.
	Some trig problems		2004-01-18
		From Weisu: I have some questions about pre-calculus. (1) (2(cos(x))^2)+3sin(x)-1=0 (2) sin(x)cos(x)=(1/2) (3) 3sin(x)=1+cos(2x) (4) tan(x)*csc(x)=csc(x)+1 (5) sin(arccsc(8/5)) (6) tan(arcsin(24/25)) (7) arccos(cos(11pi/6)) the last problem uses radian measure. Answered by Penny Nom.
	Prescription drug coverage		2003-12-04
		From Khadijah: Last week congressional approval was given to legislation involving prescription drug coverage for seniors. One summary of the legislation explains that it is estimated that in 2006 a senior will pay a premium of $35 per month, then pay their first $250 in pharmacy bills. After the bills reach $250, the coverage would pick up 75% of their bills that bring their total bills between the $250 and $2250 mark. After their bills reached a total of $2250, the senior would be responsible for all bills bringing their total annual bills between $2250 to $5100. Then any bills after the $5100 mark has been reached will be 95% covered by the insurance. Using this information, letís analyze the situation of a senior who accumulates $6000 in pharmacy bills over one year and has the insurance coverage. Over the course of this year, how many dollars will the senior pay? Answered by Penny Nom.
	root24 = 2 root6		2003-11-13
		From Burke: I know that all algerbra can be represented visually, for example: Y=9x+3 is a line on a two dimentional plane. Could Math Central please send me a visual representation of the proccess of simplifying square root like root24 equals 2root6 Answered by Penny Nom.
	Two precalculus problems		2003-08-04
		From Kate: Please help me verify the identity: cos2x(sec2x-1)=sin2x Also I am having trouble withdetermining whether f(x) is odd, even, or neither f(x)=x3-x Answered by Penny Nom.
	Contradiction in the Procedural Precedence and the Distributive property		2003-07-03
		From Arthur: When complicated expressions exist on both sides of a fraction, and both these expressions contain like and unlike terms with "literal" coefficients, the procedural precedence suddenly gets extremely confusing and seems impossible to simplify. This seems confusing and impossible to simplify because there is a HUGE contradiction in the way Procedural Precedence and the Distributive property deal with Parentheses. The Procedure says you MUST deal with what's INSIDE the parenthesis FIRST, BEFORE dealing with ANYTHING on the outside where as the Distributive property contradicts that by saying to go ahead and ignore the Precedence and use a factor on the outside of the Parenthesis. Answered by Claude Tardif.
	Subtracting rational expressions		2003-05-10
		From Simone: hi, i'm totally lost. i understand that you need to find a lowest common denominator to subtract two fractions (rational expressions) with different denominators. but what if the denominators are "x-1" and "x". is x the common denominator? if so what happens to the "-1"? do you know of any live online help i can get with the following: 3/(x-1) - (1-2x)/x i've looked through my notes and have no examples that quite match that i can follow to get through it. please help! Answered by Penny Nom.
	Excluded values		2003-02-22
		From Josh: Why do you think it is necessary to include the "excluded values" when you write your answers to rational expressions? Answered by Penny Nom.
	Rational expressions		2003-01-22
		From A student: // = the main fraction line 1.) a+1/a-1 + a-1/a+1 // a+1/a-1 - a-1/a+1 2.) 2/a(squared)-3a+2 + 2/a(squared)-a-2 // 2/a(squared)-1 + 2/ a(squared)+4a+3 Answered by Penny Nom.
	Clown has eight steps to climb		2002-11-05
		From A mom: I'm a parent of a grade two student. What is the best way to help my son figure out a math comprehension problem? Clown has eight steps to climb, is shown in a picture with front foot on third step and behind foot on first step. Each time he climbs three steps, he falls back two. How many times did he have to climb up to reach the top. Should I get him to do a line graph or math equations. On his own he came up with the answer seven. I think the answer is six. I did 0+3=3, 3-2=1, 1+3=4 and so on, In think my why is alittle confusing to him. Is there a simplier why to explain it to him. Answered by Diane Hanson.
	Simplifying Variable Expressions		2002-10-28
		From Erika: i would like to ask you a mathematical question on Simplifying Variable Expressions. The question is 2(n-4)+3. Answered by Penny Nom.
	Nixon, Jefferson, and Madison		2002-10-08
		From Lisa: The longest-lived US presidents are John Adams(age90), Herbert Hoover (also90), and Harry Truman (88). Behind them are James Madison, Thomas Jefferson, and Richard Nixon. The lattter three men lived a total of 249 years, and their ages at the time of death form consecutive odd integers. For how long did Nixon, Jefferson, and Madison live? Answered by Penny Nom.
	Rational expressions		2002-10-03
		From Ashley: 1/x(squared) + 5/xy Answered by Penny Nom.
	Variable expressions		2002-08-15
		From Brittany: I am just learning variable expressions. My homework is to write a variable expression for each word phrase; example : the number of minutes in s seconds the cost of x cartons of juice at $.75 each And etc. I don't understand it Answered by Penny Nom.
	Simplify this expression		2002-02-26
		From Francine: 2X power 5 Y power 3 times 18 X power -5 Y power -3 divided by X power 1/3 Y power 1/4. I came up with 36 ---------- X 1/3 Y 1/4 The book says 36 x1/3 y1/4. I don't get it. Answered by Penny Nom.
	Simplifying algebraic expressions		2001-05-12
		From A student: How do you simplify algebra expressions? Answered by Penny Nom.
	Adding and subtracting rational expressions		2001-05-03
		From Donna: Adding and subtracting Rational expressions. I am in grade 10 and I am a student here is an example of the questions: 1/(x+1) - 1/(x-1) = ? Answered by Penny Nom.
	Compression by a factor of ?		2001-01-12
		From Wayne: Given an equation like y = (1/2) (x-3)2 + 6, when describing the distortion from the base curve y = x2 is it correct to say there is a vertical compression by a factor of 2, or by a factor of 1/2 ? Which is more correct? I have seen both versions in different high school texts, and I am now unsure which is more correct. Answered by Harley Weston.
	Some trigonometry		2000-08-11
		From Angela: I have some PreCal questions. I am a student at the secondary level. I would be very grateful for your help. Solve the equation for theta (0 <= theta < 2pi). tan2(theta) = 3 I know sec2(theta) -1 = tan2(theta) . . . Answered by Harley Weston.
	Eligibility in a contest		2000-03-14
		From Ken Rabley: Hi, hoping you can help. Dispute among co-workers. Tell me, what is the correct answer to the following question: -1936 + (2406/4812) x (4756 - 3256) + 1250 Seems this is the question for eligibility in a contest...We have come up with various solutions, all which may be correct. Answered by Penny Nom.
	(-5)^2, -5^2 and -(5)^2		1999-10-13
		From Jennifer Brown: What is the difference between the following problems: (-5)2, -52 and -(5)2 Our text book (Beginning Algebra, fourth edition, published by McGraw Hill, by Streeter, Huthison and Hoetzle) says the second and third problem are exactly the same. I don't see how that can be. Is there a mathematical rule that explains this? Answered by Penny Nom.
	Predictions		1999-09-22
		From Joesph Dana: How do u find the results of an unbiased sample of 100 students that are shown on the table. For example the school has a total of 1,150 students prdict how many students would chose cereal(46) pancakes(15) eggs(20) and sandwich(19) Answered by Haeley Weston.
	Even and Odd Function		1999-06-17
		From Kent: There is one function with the domain of all real numbers that is both even and odd. Please give me the answer to this question before I go insane. Answered by Penny Nom.
	Shape-preserving transformations		1999-05-04
		From J McAndrew: A shape preserves its shape if a rotation, translation or scaling is performed on it. Are these the only continuous transformations which have this property? These transformations if performed on the parts and then summed have the same effect as the transformation being applied to the whole; are these linear transformations? Who, and what area of mathematics has classified all transformations of this type completely? Answered by Chris Fisher.
	A Presidential Proof		1997-03-18
		From Greg Smith: Which US president developed a proof for the Pythagorean Theorem? Where can a copy of the proof be located? Answered by Chris Fisher and Harley Weston.
	Equivalent Expressions		1997-02-26
		From Karyn Jones: Josie says that s=n/(n+1) and s/(1-s)=n are two ways to write the same formula. Describe whether or not you agree with Joise. Explain how you made your decision. Answered by Walter Whiteley and Penny Nom.
	La conjecture de Goldbach		2011-02-18
		From ahmedbenmoussa: montrez que tout nombre entier paire supérieur à 4 s'écrit somme de deux nombres premiers Answered by Claude Tardif.
	une écriture plus simple des expressions		2011-01-13
		From jessie: trouver une écriture plus simple des expressions suivantes sachant que : x + y = 3 et x - y =-2 A=x-1+y+2             B=x-1+y-2 C=x+1+y+2            C=x+1+y-2 Answered by Claude Tardif.
	Quel est le 6e nombre dans la serie suivante		2010-08-13
		From jeff: Quel est le 6e nombre dans la serie suivante: 1,2,6,42,1806,... Answered by Stephen La Rocque and Claude Tardif.
	Deux nombres consécutifs		2010-01-18
		From Janot: Bonjour comment peut on faire pour démontrer que si deux nombres sont consécutifs, leur produit et leur somme sont premiers entre eux Merci de me mettre sur la voie , j'ai échoué avec Bezout. Answered by Claude Tardif.
	2^(2^1954) est-il premier?		2005-10-04
		From Un eleve: 2(21945)+1 est-il premier? Answered by Claude Tardif.
	Nombre premier		2004-11-01
		From Katia: Pouvez-vous me dire comment savoir si un nombre est premier? Answered by Claude Tardif.
	Nombre Premier		2003-02-24
		From Un Etudiant: Montrer que si p est facteur premier de 22n + 1 alors (p-1) est multiple de 2n+2 Answered by Claude Tardif.
	preuve par 9		2001-04-04
		From Michel: Pourriez-vous m'expliquer en détail comment fonctionne la preuve par 9 (pour une division et une multiplication). Je sais l'appliquer mais je ne sais pas pourquoi ça marche. Je ne retrouve pas la démonstration. Merci de m'aider. Exemple . 17x2=34 ; preuve par neuf : 1+7=8 ; 8x2= 16 ; 1+6=7 et 3+4=7, on peut donc supposer (sans affirmer) que cette multiplication a un résultat juste car la preuve par 9 est bonne, 7=7. Comment fonctionne cette preuve par 9??? Answered by Claude Tardif.

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