因式分解 (1)x2-2x-8 (2)x2(x-1)-4(1-x)2.

问题描述:

因式分解
(1)x2-2x-8
(2)x2(x-1)-4(1-x)2

(1)x2-2x-8=(x-4)(x+2);
(2)x2(x-1)-4(1-x)2
=(x-1)[x2-4(x-1)
=(x-1)[x2-4x+4)
=(x-1)(x-2)2