计算：(1)(3y2+12x)(12x-3y2)；(2)(x-12)(x+12)(x2+14)；(3)(x4+y4)(x2+y2)(x+y)(x-y)；(4)(x+y)(x-y)+(x+2y)(x-2y).

解：(1)原式=(12x)2-(3y2)2=14x2-9y4；

(2)原式=(x2-14)(x2+14)=x4-116；

(3)原式=(x2-y2)(x2+y2)(x4+y4)=(x4-y4)(x4+y4)=x8-y8；

(4)原式=x2-y2+x2-4y2=2x2-5y2.

标签：3y2,12x