Question

Which is a solution to (x-2)(x+5)=18?
A. x= -10
B. x= -7
C. x= -4
D. x= -2

Answer 1

B

Explanation:

Since you are given options, simply plug in numbers.

A won’t work because (-10+5) = -5 and 18 clearly is not divisible by 5.

B works:

(-7-2)(-7+5) = -9(-2) = 18

Answer 2

x = -7

Explanation:

(x-2)(x+5)=18

We can substitute the possible solutions in and see if they are true

x = -10

(-10-2)(-10+5)=18

-12 * -5 = 18

60 =18

False

x = -7

(-7-2)(-7+5)=18

-9 *-2 = 18

18 = 18 True

x = -4

(-4-2)(-4+5)=18

-6 *1 = 18

-6 = 18

False

x=-2

(-2-2)(-2+5)=18

-4 *3 =18

-12 = 18

False