把下列各式因式分解. (1)4x(a-b)-8y(b-a) (2)-36x2+12xy-y2 (3)a4-16.

问题描述:

把下列各式因式分解.
(1)4x(a-b)-8y(b-a)
(2)-36x2+12xy-y2
(3)a4-16.

(1)4x(a-b)-8y(b-a)
=4(a-b)(x+2y);
(2)-36x2+12xy-y2
=-(36x2-12xy+y2
=-(6x-y)2
(3)a4-16
=(a2+4)(a2-4)
=(a2+4)(a-2)(a+2).