数学题啊,10分钟内回复!

问题描述:

数学题啊,10分钟内回复!
已知x分之1-y分之1=4,求分式(x+3xy-y)分之(2x-xy-2y)的值

x分之1-y分之1=41/x - 1/y = 4y - x = 4xyxy = y/4 - x/4,代入 (2x-xy-2y)/(x+3xy-y),得:(2x - y/4 + x/4 - 2y)/(x + 3y/4 - 3x/4 - y)= (9x/4 - 9y/4)/ (x/4 - y/4)= 9