a) Tính tích: (x + 1)(x^2 – x + 1);
Giải thích
a) Ta có: (x + 1)(x2 – x + 1)
= x . x2 – x . x + x . 1 + x2 – x + 1
= x3 – x2 + x + x2 – x + 1
= x3 + (x2 – x2) + (x – x) + 1 = x3 + 1.
a) Ta có: (x + 1)(x2 – x + 1)
= x . x2 – x . x + x . 1 + x2 – x + 1
= x3 – x2 + x + x2 – x + 1
= x3 + (x2 – x2) + (x – x) + 1 = x3 + 1.