因式分解: (1)4x2-16; (2)3m2n-12mn+12n; (3)(a2+ab+b2)2-9a2b2.

问题描述:

因式分解:
(1)4x2-16;     
(2)3m2n-12mn+12n;      
(3)(a2+ab+b22-9a2b2

(1)原式=4(x2-4)
=4(x+2)(x-2);
(2)原式=3n(m2-4m+4)
=3n(m-2)2
(3)原式=(a2+ab+b2-3ab)(a2+ab+b2+3ab)
=(a2-2ab+b2)(a2+4ab+b2
=(a-b)2(a2+4ab+b2).