已知1/x-1/y=2,求(3x+5xy-3y)/(x-xy-y)的值如题

问题描述:

已知1/x-1/y=2,求(3x+5xy-3y)/(x-xy-y)的值
如题

1/x-1/y=2,
(y-x)/xy=2
2xy=y-x
(3x+5xy-3y)/(x-xy-y)
=(-6xy+5xy)/(-2xy-xy)
=-xy/-3xy
=1/3

1/x-1/y=2
y-x=2xy
x-y=-2xy
(3x+5xy-3y)/(x-xy-y)
=(-xy)/(-3xy)
=1/3