1、当1/x-1/y=5时,求分式(3x+5xy-3y)÷(x-3xy-y)的值.

问题描述:

1、当1/x-1/y=5时,求分式(3x+5xy-3y)÷(x-3xy-y)的值.

1/x-1/y=5
y-x=5xy
(3x+5xy-3y)÷(x-3xy-y)
=(-15xy+5xy)/(-5xy-3xy)
=-10xy/(-8xy)
=5/4