已知x分之1+y分之1=2,求分式2x-5xy+2y分之3x+7xy+3y的值._数学解答

已知x分之1+y分之1=2,求分式2x-5xy+2y分之3x+7xy+3y的值.

人气：406 ℃　时间：2019-10-11 02:58:51

解答

1/x+1/y=2
(x+y)/(xy)=2
x+y=2xy
(3x+7xy+3y)/(2x-5xy+2y)
=[3(x+y)+7xy]/[2(x+y)-5xy]
=(6xy+7xy)/(4xy-5xy)
=(13xy)/(-xy)
=-13