Question

Decide whether or not the functions are inverses of each other.

f(x) = 3x + 9, g(x) = x - 3

Answer 1

if they are inverse then
f(g(x)=1

find f(g(x).

Answer 2

for f(x) replace it with y. so you have y = 3x+9. solve for x, then replace all x's with y's and all y's with x's and you have the inverse of f(x).