Which of the following values is a solution of 3|5 + x| = 12?

a. 7

b. 1

c. –9

d. –17

It is easiest to simply just substitute any of the choices into the original equation and see which one satisfies the equation.

Given the equation: 3 * |5 + x| = 12

Using choice A. x = 7
3 * |5 + 7| = 12
36 =/= 12

Using choice B. x = 1
3 * |5 + 1| = 12
18 =/= 12

Using choice C. x = -9
3 * |5 + -9| = 12
12 = 12

Therefore, the correct answer is C. -9