将分式(2x+3xy-2y)/(x-2xy-y)的分子分母同除以xy(因为xy不为零),
(2x+3xy-2y)/(x-2xy-y)
=（2/y+3-2/x)/(1/y-2-1/x）
=[3-2(1/x-1/y)]/[-2-(1/x-1/y)]
=(3-2*3)/(-2-3)
=3/5