Quandaries and Queries
 

 

Simplify:
 
-3x (x2 + 2)
 
(x + 2) (x + 3)
 
I need help on these, learning how to set them up step by step to get a answer :) Thank you so much.
Tiff
 

 

Hi Tiff,

The first problem is to exand -3x times (x2 + 2). When you multiply an algebraic quantity times the sum of two other quantities you need to multiply the first quantity by each of the other two and then add them. That is to multiply -3x times (x2 + 2) you need to multiply -3x times x2 and -3x times 2 and then add. Algebraically this is (I an going to use for multiplication)

-3x (x2 + 2) = -3x x2 + -3x 2

x times x2 is x3 and -3 times 2 is -6 so this simplifies to

-3 x3 - 6x

The second problem is also an algebraic quantity (x+2) times the sum of two other quantities x and 3. Thus

(x+2) (x+3) = (x+2) x + (x+2) 3

But this can be written

x (x+2) + 3 (x+2)

Expand these two expressions the same way and then collect like terms.

Penny

 
 

Go to Math Central