因式分解: (1)(a+b)x2-(a+b); (2)9(a+b)2-4(a-b)2; (3)6xy2-9x2y-y3; (4)4+12(x-y)+9(x-y)2.

问题描述:

因式分解:
(1)(a+b)x2-(a+b);
(2)9(a+b)2-4(a-b)2
(3)6xy2-9x2y-y3
(4)4+12(x-y)+9(x-y)2

(1)(a+b)x2-(a+b)=(a+b)(x2-1)=(a+b)(x+1)(x-1);(2)9(a+b)2-4(a-b)2=[3(a+b)+2(a-b)][3(a+b)-2(a-b)]=(3a+3b+2a-2b)(3a+3b-2a+2b)=(5a+b)(a+5b);(3)6xy2-9x2y-y3=-y(y2-...