因式分解: (1)3x-12x3 (2)1-m2+2mn-n2.

问题描述:

因式分解:
(1)3x-12x3
(2)1-m2+2mn-n2

(1)3x-12x3
=3x(1-4x2),
=3x(1-2x) (1+2x);
(2)1-m2+2mn-n2=1-(m2-2mn+n2),
=12-(m-n)2
=(1+m-n)(1-m+n).