x³ -1 = x³ + (x²-x²) +(x -x) -1 =
x³ +x²+x - x²-x -1 =
x(x²+x+1) - 1(x²+x+1) =
(x²+x+1)(x-1)
Răspuns:
x³-1=x³-1³=(x-1)(x²+x×1+1²)=(x-1)(x²+x+1²)=(x-1)(x²+x+1)
