Question

Which of the following are solutions to2x^2-8x-90? Select all that apply. 2

-5
-7
9
15
5
7

Answer 1

9,-5

Explanation:

2x^2-8x-90

Factor by 2

2(x^2 -4x-45)

What two numbers multiply to -45 and add to -4

-9*5 = -45

-9+5 = -5

2(x-9) (x+5)

Set this equal to zero

2(x-9) (x+5) =0

Divide by 2

(x-9) (x+5) =0

Using the zero product property

x-9=0 x+5=0

x=9 x=-5