问题
解答题
已知M=
|
答案
∵M=
，N=x2+y2 x2-y2
，2xy x2-y2
∴N+M=
=x2+y2+2xy x2-y2
=(x+y)2 (x+y)(x-y)
；N-M=x+y x-y
=x2+y2-2xy x2-y2
=(x-y)2 (x+y)(x-y)
．x-y x+y
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已知M=
|
∵M=
，N=x2+y2 x2-y2
，2xy x2-y2
∴N+M=
=x2+y2+2xy x2-y2
=(x+y)2 (x+y)(x-y)
；N-M=x+y x-y
=x2+y2-2xy x2-y2
=(x-y)2 (x+y)(x-y)
．x-y x+y