1:原式=xy(x^2-2xy+y^2)=xy(x-y)^22:原式=(5a)^2-2*2*5*ab+(2b)^2=(5a-2b)^23:原式=xy(x^2-2xy+y^2)=xy(x-y)^24:原式=(x^2-4x+4)^2=(x-2)^45:原式=[(a-b)^2-(b-a)][(a-b)^2+(b-a)]=(a^2+b^2-2ab-b+a)(a^2+b^2-2ab+b-a)望采纳！
用写过程吗
