一道超级难的题目的说.

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一道超级难的题目的说.

一道超级难的题目的说.
一道超级难的题目的说.
 

一道超级难的题目的说.
x-y-x2+y2=(x-y)-(x2-y2)

分母不等于零。两个等式,解x,y

明天给你写下来

你下次别做标题党了,这是基础题
我没相机打给你吧
x-y-x^2+^2=(x-y)(1-x-y)
1-x^2-2xy-y^2...

全部展开

分子(1+2y)
分母(x-y)(1-x-y)(1+x+y)

收起

原式=1[(x-y)-(x²-y²)]-1/[1-(x²+2xy+y²)]
=1/[(x-y)-(x+y)(x-y)]-1/[(1-(x+y)²)]
=1/[(x-y)(1-x-y)]-1/[(1+x+y)(1-x-y)]
=[(1+x+y)-(x-y)]/[(x-y)(1-x-y)(1+x+y)]
=(1+x+y-x+y)/(x-y)(1-x-y)(1+x+y)]
=(1+2y)/[(x-y)(1-x-y)(1+x+y)]