急··已知x/3=y/5=z/7,求(x+z-y)/y和(2x+3y+4z)/(5x-3y+z)

问题描述:

急··已知x/3=y/5=z/7,求(x+z-y)/y和(2x+3y+4z)/(5x-3y+z)
1个回答 分类:综合 2014-12-13

问题解答:

我来补答
设x/3=y/5=z/7=k,则
x=3k,y=5k,z=7k,
代入(x+z-y)/y和(2x+3y+4z)/(5x-3y+z)中
(x+z-y)/y
=(3k+7k-5k)/(5k)
=5k/(5k)
=1
(2x+3y+4z)/(5x-3y+z)
=(6k+15k+28k)/(15k-15k+7k)
=49k/(7k)
=7
 
 
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