若2/x+2/y=1,则（2x-xy+2y）/（3x+5xy+3y）=?_数学解答

若2/x+2/y=1,则（2x-xy+2y）/（3x+5xy+3y）=?

人气：229 ℃　时间：2020-03-17 11:12:23

解答

2/x+2/y=1
2(x+y)/xy=1
2(x+y)=xy
(x+y)=xy/2
(2x-xy+2y)/(3x+5xy+3y)
=(xy-xy)/(13xy/2)
=0