初一分式运算3
问题描述：
初一分式运算3
化简x^2+xy/x^2-xy÷（x+y)÷ -xy/y^2-xy的结果是________________.
答
原式=[x(x+y)/x(x-y)]÷(x+y)÷[-xy/y(y-x)]
=[(x+y)/(x-y)]×[1/(x+y)]×[(x-y)/x]
=[(x+y)(x-y)]/[x(x-y)(x+y)]
=1/x