解:1/x+1/y=2
x+y=2xy
(2x+3xy+2y)/(x-xy+y)=[2(x+y)+3xy]/[(x+y)-xy]
=(4xy+3xy)/(2xy-xy)
=7xy/xy
=7
2X+3XY+2Y/ X-XY+Y 是2X+3XY+2Y/( X-XY)+Y 还是2X+3XY+2Y/ X-XY+Y??