1/x-1/y=3 求x-3xy-y/2x-xy-2y 等于多少

问题描述:

1/x-1/y=3 求x-3xy-y/2x-xy-2y 等于多少

1/x-1/y=3

x-y=-3xy
x-3xy-y/2x-xy-2y
=(-3xy-3xy)/(-6xy-xy)
=6/7