F(x)=2x+1 , g(x)=x-2 dan h(x)=x²+1 , apabila (f°g°h)(x)=1 nilai x adalah

(fogoh)(x) = 1
(fog)(x^2 + 1) = 1
f((x^2 + 1) – 2 = 1
f (x^2 – 1) = 1
2(x^2 – 1) + 1 = 1
2x^2 – 2 + 1 = 1
2x^2 – 1 = 1
2 x^2 = 1 + 1
2x^2 = 2
x^2 = 2/2
x = akar 1
x = 1