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.
答
(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).