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已知1/x-1/y=-3,求3x-5xy-3y/x-2xy-y的值
题目详情
已知1/x-1/y=-3,求3x-5xy-3y/x-2xy-y的值
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答案和解析
1/x-1/y=3
通分有y-x/xy=3 所以y-x=3xy
(3x-5xy-3y)/(x-2xy-y)=[3(x-y)-5xy]/[(x-y)-2xy]=(-9xy-5xy)/(-3xy-2xy)
=(-14xy)/(-5xy)=14/5
通分有y-x/xy=3 所以y-x=3xy
(3x-5xy-3y)/(x-2xy-y)=[3(x-y)-5xy]/[(x-y)-2xy]=(-9xy-5xy)/(-3xy-2xy)
=(-14xy)/(-5xy)=14/5
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