Hi my name is anthony, the level is middle, and i am a student.


I have a question to help me study for a math exam coming up on january 30.

Here is the question, and i don't know how to graph it either, so if you can please include a picture or web site that shows the labeled graph:

Given -1.7x + 0.8y=7.1:

(a) state the intercepts and slope for the graph

(b) Draw the graph

Hi Anthony,

To find the x intercept you need to find where the graph crosses the x-axis. All the points on the x-axis have their y-coordinate equal to zero. Thus, in the equation, set y = 0 and solve for x.

-1.7x + 0.8y = 7.1 set y = 0
-1.7x + 0.8 0 = 7.1
-1.7x = 7.1
y = ^7.1/_-1.7 = - 4.17

Thus the x intercept is - 4.17

To find the y intercept you need to find where the graph crosses the y-axis. All the points on the y-axis have their x-coordinate equal to zero. Thus, in the equation, set x = 0 and solve for y.

-1.7x + 0.8y = 7.1 set x = 0
-1.7 0 + 0.8y = 7.1
0.8y = 7.1
y = ^7.1/_0.8 = 8.88

Thus the y intercept is 8.88

Now that you know two points on the graph you can use a ruler and draw the graph

Finally, the slope you can find two ways. The first method is to read the rise and run from the graph.

So the slope is m = ^8.88/_4.17 = 2.1

The second method is to use the equation. To do this you need to put the equation into the form

y = m x + b

and then m is the slope.

The equation you have is

-1.7x + 0.8y = 7.1

add 1.7x to both sides to get

0.8 y = 1.7 x + 7.1

Now divide both sides by 0.8 to get

y = 2.1 x + 8.9

Thus the slope is 2.1

I hope this helps,
Penny