ditentukan g(f(x))=f(g(x)). jika f(x)=2x+p dan g(x)=3x+120, maka nilai p....

f(x) = 2x + p
g(x) = 3x + 120
f(g(x)) = 2(3x + 120) + p = 6x + 240 + p
g(f(x)) = 3(2x + p) + 120 = 6x + 3p + 120
jika f(g(x)) = g(f(x)), maka
6x + 240 + p = 6x + 3p + 120
6x - 6x + 240 - 120 = 3p - p
120 = 2p
p = 120 : 2 = 60

g(f(x))=g(2x+p)=3(2x+p)+120=6x+3p+120

f(g(x))=f(3x+120)=2(3x+120)+p=6x+240+p

g(f(x))=f(g(x))
6x+3p+120=6x+p+240
3p-p=240-120
2p=120
P=120/2=60