Diketahui f(x) = 2x -1 dan g(x) = 4x+p jika (fog) (x) = (gof) (x). Maka nilai p= ?

Diketahui f(x) = 2x -1 dan g(x) = 4x+p jika (fog) (x) = (gof) (x). Maka nilai p= ?

Jawab
(fog)(x) = (gof)(x)

f(g(x)) = g(f(x))

f(4x+p) = g(2x-1)

2(4x+p) = 4(2x-1)+p

8x +2p = 8x -4 +p

2p =p-4

p = -4