Question

The area of a rectangular painting is given by the trinomial x2 + 2x – 15. What are the possible dimensions of the painting? Use factoring. (1 point)
(x + 5) and (x – 3)
(x + 5) and (x + 3)
(x – 5) and (x – 3)
(x – 5)and (x + 3)

Answer 1

x^2 + 2x - 15
= x^2 + 5x - 3x - 15

can you continue?

Answer 2

- factor by grouping

Answer 3

i'm not sure how to do that.

Answer 4

factor x^2 + 5x by taking out the x

then take out -3 for the other 2 terms

Answer 5

x(x + 5) - 3( )

what will go in the second parenthesis?

Answer 6

Factorize the -15.

-15 = 5 x (-3) = (-5) x 3 = 15 x (-1) = -15 x (1)

In here we must sum factors to get to +2. We must look which factors add upt to +2.
it is (5 x (-3)) so the answer is:
(x + 5) and (x -3)

Answer 7

you can find what goes into the second bracket by dividing -3x - 15 by -3