解比例:X:0.5=3/4 1/2:X=1/6:2/5 7/2:X=3/5:1/7

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希望则拦采纳孙简胡，学咐指习进步

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X:0.5=3/4 x=0.5*3/4=3/8
1/2:X=1/6:2/5 x=1/2*(2/5)/(1/轿世薯返凳6)=6/5
7/2:X=3/闭者5:1/7 x=(7/2)*(1/7)/(3/5)=5/6

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