答：
2y+3/y=x
2y^2+3=xy
xy-2y^2=3
(x-y)(x-2y)-(2y-x)^2
=(x-y)(x-2y)-(x-2y)^2
=(x-2y)(x-y-x+2y)
=(x-2y)y
=yx-2y^2
=3雖然剛發(fā)完一分鐘就找到答案了 還是謝謝你啊不客氣，祝你學(xué)習(xí)進(jìn)步