jika g(x) = 6x+1 dan (f o g)(x) = 4-2x, maka f(3x) = ....

jawab

g(x) = 6x + 1
fog (x) = 4 - 2x
f { g(x)} = 4 - 2x
f (6x +1) = 4 - 2x
f(x) = 4 - 2 { 1/6 (x -1)}
f(x) = 4 - 1/3 (x  -1)
f(3x) = 4 - 1/3 (3x -1)
atau
f(3x) = 4 - x + 1/3
f(3x) = 13/3 - x