G(x) = x²-3x+1 dan f°g(x)=2x²-6x+1 , nilai f(x)

(f o g)(x) = 2x^2 – 6x + 1
f(g(x)) = 2x^2 – 6x + 2 – 1
f(x^2 – 3x + 1) = 2(x^2 – 3x + 1) – 1
f(x) = 2x – 1