Diketahui fungsi f: R->R dan g: R->R dirumuskan dengan f (x) = x-1/x, untuk x#0 dan g (x) = x + 3. Tentukanlah (gof (x))^-1

gof(x) = (x-1)/x + 3
= (x-1)/x + 3x/x
= (x - 1 + 3x) / x
= (4x - 1)/x
invers
y = (4x - 1)/x
yx = 4x - 1
yx - 4x = -1
x(y - 4) = -1
x = -1/(y - 4)
(fog)-¹(x) = -1 / (x - 4)