G(x) = 4x-1g0f(x) = 12x-1f(x) = ????

g(x) = 4x-1
g0f(x) = 12x-1
f(x) = ????

gof(x)= g(f(x))
12x-1= 4 f(x) -1
12x = 4 f(x)
f(x) = 3x