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

Question

Jesse Lutz

Mathematics

1 April, 02:46

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

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Answers (1)

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Green Giant · Answer 1

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