初二数学题求解,要有步骤说明已知5x-7y=0,求(x-y)/(x+y)的值

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初二数学题求解,要有步骤说明已知5x-7y=0,求(x-y)/(x+y)的值初二数学题求解,要有步骤说明已知5x-7y=0,求(x-y)/(x+y)的值初二数学题求解,要有步骤说明已知5x-7y=0,

初二数学题求解,要有步骤说明已知5x-7y=0,求(x-y)/(x+y)的值
初二数学题求解,要有步骤说明
已知5x-7y=0,求(x-y)/(x+y)的值

初二数学题求解,要有步骤说明已知5x-7y=0,求(x-y)/(x+y)的值
5x-7y=0,
5x=7y
x=7/5y
(x-y)/(x+y)
=2/5y/(12/5y)
=2/5*5/12
=1/6

∵5x-7y=0
∴X=7Y/5
∴(x-y)/(x+y)=﹙7Y/5-Y﹚/﹙7Y/5+Y﹚=﹙2/5﹚Y/﹙12/5﹚Y=﹙2/5﹚×﹙5/12﹚=1/6