c) x^3 – 9x^2 + 27x – 27;
c) x3 – 9x2 + 27x – 27;
c) x3 – 9x2 + 27x – 27 = x3 – 3 . x2 . 3 + 3 . x . 32 – 33 = (x – 3)3;