已知xy/x-y=1/2 求3x-5xy-3y/y+3xy-x的值!

问题描述:

已知xy/x-y=1/2 求3x-5xy-3y/y+3xy-x的值!

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