Maka f (x+1) sama dengan...

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

Jawaban: D