因式分解: (1)9(m+n)2-16(m-n)2; (2)(x+y)2+10(x+y)+25; (3)4a2b2-(a2+b2)2.

问题描述:

因式分解:
(1)9(m+n)2-16(m-n)2
(2)(x+y)2+10(x+y)+25;
(3)4a2b2-(a2+b22

(1)原式=[3(m+n)+4(m-n)][3(m+n)-4(m-n)]=(7m-n)(-m+7n);
(2)原式=(x+y+5)2
(3)原式=(2ab+a2+b2)(2ab-a2-b2)=-(a-b)2(a+b)2