已知x分之1-y分之1=5,求分式3x+5xy-3y分之x-3xy-y的值

问题描述:

已知x分之1-y分之1=5,求分式3x+5xy-3y分之x-3xy-y的值

1/X-1/Y=5
Y-X=5XY,
(X-3XY-Y)/(3X+5XY-3Y)
=[-(Y-X)-3XY]/[-3(Y-X)+5XY]
=(-8XY)/(-10XY)
=4/5.