Given f(x)=1/4x+2, what is the value of x if f(x)=-8

Question

given f(x) = 1/4x+2, what's is the value of x if f(x) = -8

Answer 1

f(x) = x/4 + 2

-8 = x/4 + 2          substitute

-10 = x/4              subtract 2 form both sides

-40 = x                 multiply both sides by 4

 

f(-40) = -8