问题
解答题
计算：
|
答案
原式=
-x-y 2(x+y) x2+y2 (x+y)(x-y)
=
-(x-y)(x-y) 2(x+y)(x-y) 2(x2+y2) 2(x+y)(x-y)
=x2-2xy+ y2-2x2-2y2 2(x+y)(x-y)
=-
．x+y 2(x-y)
搜题请搜索小程序“爱下问搜题”
计算：
|
原式=
-x-y 2(x+y) x2+y2 (x+y)(x-y)
=
-(x-y)(x-y) 2(x+y)(x-y) 2(x2+y2) 2(x+y)(x-y)
=x2-2xy+ y2-2x2-2y2 2(x+y)(x-y)
=-
．x+y 2(x-y)