已知2/X-1/Y=3,则(X-2Y-XY)/(5XY+6Y-3X)=?_其他解答

已知2/X-1/Y=3,则(X-2Y-XY)/(5XY+6Y-3X)=?

人气：199 ℃　时间：2019-10-02 20:29:48

解答

2/X-1/Y=3
(2Y-X)/XY=3
2Y-X=3XY
X-2Y=-3XY
(X-2Y-XY)/(5XY+6Y-3X)
=[(X-2Y)-XY]/[5XY-3(X-2Y)]
=(-3XY-XY)/(5XY+9XY)
=-4XY/14XY
=-2/7