Phân tích các đa thức sau thành nhân tử: c) x3 – x2 – x + 1.
Giải thích
c) x3 – x2 – x + 1
= (x3 – x2) – (x – 1)
= x2(x – 1) – (x – 1)
= (x – 1)(x2 – 1)
= (x – 1)(x + 1)(x – 1)
= (x – 1)2(x + 1).
c) x3 – x2 – x + 1
= (x3 – x2) – (x – 1)
= x2(x – 1) – (x – 1)
= (x – 1)(x2 – 1)
= (x – 1)(x + 1)(x – 1)
= (x – 1)2(x + 1).