已知x-y=xy,求(2x-xy-2y)/(x-2xy-y)的值
问题描述:
已知x-y=xy,求(2x-xy-2y)/(x-2xy-y)的值
答
x-y=xy
2x-xy-2y=2xy-xy=xy
x-2xy-y=xy-2xy=-xy
所以(2x-xy-2y)/(x-2xy-y)=xy/-xy=-1