Question

15) Solve. −x2 = 2x − 15 A) x = 3, x = 5 B) x = −3, x = 5 C) x = 3, x = −5 D) x = −3, x = −5

Answer 1

Answer:

x=-5                   x=3

Step-by-step explanation:

−x2 = 2x − 15

Add x^2 to each side

x^2−x2 =x^2+ 2x − 15

0 = x^2+ 2x − 15

Factor

What two numbers multiply to -15 and add to 2

5*-3 = -15

5-3 =2

(x+5) (x-3) =0

Using the zero product property

x+5 =0        x-3=0

x+5-5=0-5    x-3+3=0+3

x=-5                   x=3