已知xy/x+y=二分之一,求分式3x-xy+3y/x-xy+y的值_数学解答

已知xy/x+y=二分之一,求分式3x-xy+3y/x-xy+y的值

人气：318 ℃　时间：2019-08-22 11:34:21

解答

xy/x+y=1/2
xy=2(x+y)
3x-xy+3y/x-xy+y
=[3(x+y)-2(x+y)]/[(x+y)-2(x+y)]
=(x+y)/[-(x+y)]
=-1