1,b(a-b)²-(a-b)³
2,a²(x-y)²+2a(x-y)³
3,(x-2)²-y(2-x)²
4,5(x-y)³+10(y-x)²
5,10a(x-y)³-5b(y-x)²
邮箱: 联系方式: