Diket f(x) 3x+1 dan (fog)(x) =7-9x,tentukan nilai g^-1(x)

(fog)(x) = 7-9x
f(g(x)) = 7-9x
3.g(x)+1 = 7-9x
3.g(x) = 7-9x-1
3.g(x) = 6-9x
g(x) = (6-9x)/3
g(x) = 2-3x
y = 2-3x
3x = 2-y
x = (2-y)/3

g^-1(x) = (2-x)/3