1/x-1/y=3,则求3y+xy-3x/2x-xy-2y
问题描述:
1/x-1/y=3,则求3y+xy-3x/2x-xy-2y
答
y-x=3xy
(3y+xy-3x)/(2x-xy-2y)=10xy/(-7xy)=10/7