x的平方减xy分之y 减 y的平方减xy分之x 等 - 知识问答

x的平方减xy分之y 减 y的平方减xy分之x 等于多少

1个回答

如果题目是:"x的平方减xy分之y加 y的平方减xy分之x ",那么就是你的那个答案.
y/(x^2-xy)+x/(y^2-xy)
=y/[x(x-y)]+x/[y(y-x)]
=y^2/[xy(x-y)]-x^2/[xy(x-y)]
=(y^2-x^2)/[xy(x-y)]
=(y-x)(y+x)/[xy(x-y)]
=-(x-y)(x+y)/[xy(x-y)]
=-(x+y)/xy
你再检查一下是不是题目打错了.

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