已知3x=xy+3y,求2x+xy-2y/y-x-xy的值

问题描述:

已知3x=xy+3y,求2x+xy-2y/y-x-xy的值

3x=xy+3y,
xy=3x-3y
2x+xy-2y/y-x-xy
=(2x+3x-3y-2y)/(y-x-3x+3y)
=(5x-5y)/[-(2x-2y)]
=5/(-2)
=-5/2