Bài 1: Phân tích nhân tử
a) (x2 + x + 1)(x2 + x + 2) - 12
b) (x2 + 3x + 1)(x2 + 3x + 2) - 6
c) x(x + 1)(x + 2)(x + 3) + 1
d) (x + 2)(x + 3)(x + 4)(x + 5) - 24
e) (4x + 1)(12x - 1)(3x + 2)(x + 1) - 4
f) (x2 + 6x + 5)(x2 + 10x + 21) + 15
g) x4 + (x - 4)4 - 82
h) (x2 - a)2 - 6x2 + 4x + 2a