f(3x-1)=6x + 5 tentukan f(5)

misal :
a = 3x - 1
a + 1 = 3x
x = a/3 + 1/3

kemudian masukkan ke :
f(3x - 1) = 6x + 5
f(a) = 6.(a/3 + 1/3) + 5
f(a) = 2a + 2 + 5
f(a) = 2a + 7

maka : 
f(X) = 2X + 7

JADI :
f(5) = 2.(5) + 7
f(5) = 10 + 7
f(5) = 17