x^3 - 7x + 6
= x^3 - x^2 + x^2 - x - 6x + 6
= x^2(x - 1) + x(x - 1) - 6(x - 1)
= (x - 1)(x^2 + x - 6)
= (x - 1)(x^2 + 3x - 2x - 6)
= (x - 1)[x(x + 3) - 2(x + 3)]
= (x - 1)(x + 3)(x - 2)
Đúng 0
Bình luận (0)