diketahui g(x)=5+2x,f(x)=3+x,dan h(x)=3x.Bila ( g . f . h)^-1(x)=-5,maka nilai x adalah

gofoh(x) = g(f(h(x))) = g(f(3x)) = g(3+3x) = 5+2(3+3x)
gofoh(x) = 11 + 6x
6x = y - 11
x = (y - 1)/6
gofoh^-1(x) = (x - 1)/6 = -5
x - 1 = -30
x = -29