2（a²+b²)(a+b)²-(a²-b²)²

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
=[2a²+2b²-(a²+b²-2ab)](a+b)²
=(a²+b²+2ab)(a+b)²
=(a+b)²(a+b)²
=(a+b)^4
4（1+2x-3y）+(3y-2x)²
=4+4(2x-3y)+(2x-3y)²
=(2x-3y+2)²
（x+y)²-4(x+y-1)
=（x+y)²-4(x+y)+4
=（x+y-2)²
3（a-2）²-(3a-2)+27(2-3a)
=3(a-2)²-(3a-2)-27(3a-2)
=3(a-2)²-28(3a-2)
=[3(a-2)-28](3a-2)
=[3a-6-28](3a-2)
=(3a-34)(3a-2)