已知x分之1+y分之1=2,求分式2x-5xy+2 - 知识问答

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

1个回答

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

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