已知1/x+1/y=2,求分式3x+7xy+3y/2x-5xy+2y的值

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

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