xy/(x+y)=3,
xy=3(x+y),
(2x-3xy+2y)/(3xy-x-y)
=[2(x+y)-3xy]/[3xy-(x+y)]
=[2(x+y)-3*3(x+y)]/[3*3(x+y)-(xy)]
=-7(x+y)/8(x+y)
=-7/8.