拜托了①（a-b)^4-(a+b)^2 ②2(x-y)(x+y)-(x+y)^2-(x-y)^2
问题描述：
拜托了①（a-b)^4-(a+b)^2 ②2(x-y)(x+y)-(x+y)^2-(x-y)^2
答
①（a-b)^4-(a+b)^2=[(a-b)²+a-b]*[(a-b)²-a-b]
②2(x-y)(x+y)-(x+y)^2-(x-y)^2 =-[(x+y)²-2(X+y)(x-y)+(x-y)²]=-[(x+y)-(x-y)]²=-4y²第一个好像错了