Jika f(x)=x²-3x+2 dan g(x)=2x+1,maka(fog)(x)=

f(x) = x^2 - 3x + 2
g(x) = 2x + 1
(fog)(x)
= f(g(x))
= (2x+1)^2 - 3(2x+1) + 2
= 4x^2 + 4x + 1 - 6x - 3 + 2
= 4x^2 - 2x

Perhatikan bahwa [tex]f(x)=(x-1)(x-2)[/tex].
[tex](f\circ g)(x)=f(g(x))\\ (f\circ g)(x)=f(2x+1)\\ (f\circ g)(x)=(2x+1-1)(2x+1-2)\\ (f\circ g)(x)=2x(2x-1)\\ \therefore (f\circ g)(x)=4{ x }^{ 2 }-2x[/tex]