Question

Given the function f(x) = 2(x + 8), find x if f(x) = 12.

A) 2
B) 40
C) −2
D) 14

Answer 1

f(x) = 2(x+8)
12 = 2x + 16
2x = 12 - 16
2x = -4
x = -2

Answer 2

f(x)= 2 × (x+8)------(1)

f(x)=12---------(2)

Equating (1) and (2)

⇒2×(x+8)=12

⇒Using distributive property of multiplication with respect to Addition

⇒2 x +16=12

⇒2 x+16-16=12 -16-----[Subtracting 16 from both sides]

⇒2 x= -4

Dividing by , 2 ,on both sides

⇒x= -2

Option C: -2