2(a²+b²)(a+b)²-(a²-b²)²

问题描述:

2(a²+b²)(a+b)²-(a²-b²)²
4(1+2x-3y)+(3y-2x)²
(x+y)²-4(x+y-1)
3(a-2)²-(3a-2)+27(2-3a)

2(a²+b²)(a+b)²-(a²-b²)²=2(a²+b²)(a+b)²-[(a-b)(a+b)]²=2(a²+b²)(a+b)²-(a-b)²(a+b)²=[2(a²+b²)-(a-b)²](a+b)²...