计算 (1)(a-b+c-d)(c-a-d-b); (2)(x+2y)(x-2y)(x4-8x2y2+16y4).

问题描述:

计算
(1)(a-b+c-d)(c-a-d-b);
(2)(x+2y)(x-2y)(x4-8x2y2+16y4).

(1)原式=[(c-b-d)+a][(c-b-d)-a]
=(c-b-d)2-a2
=c2+b2+d2+2bd-2bc-2cd-a2
(2)∵x4-8x2y2+16y4=(x2-4y22
∴原式=(x2-4y2)(x2-4y22=(x2-4y23
=(x23-3(x22(4y2)+3x2•(4y22-(4y23
=x6-12x4y2+48x2y4-64y6