解:(2Y-3XY-2X)/(Y+2XY-X) =[2(Y-X)-3XY]/[(Y-X)+2XY]因:1/X-1/Y=3 =(Y-X)/XY=3所以:Y-X=3XY 原式=[2(Y-X)-3XY]/[(Y-X)+2XY] =[2*3-3*1]/[3+2*1] =3/5
1/X-1/Y=3Y-X=3XY(2Y-3XY-2X)=3XY(Y+2XY-X)=5XY(2Y-3XY-2X)/(Y+2XY-X)=3/5
3/5