已知:x/3=y/5=z/7,求代数式x+y+3z/3y-2z-x的值

问题描述:

已知:x/3=y/5=z/7,求代数式x+y+3z/3y-2z-x的值

设x/3=y/5=z/7=k
∴x=3k,y=5k,z=7k
∴(x+y+3z)/(3y-2z-x)
=(3k+5k+21k)/(15k-14k-3k)
=29k/(-2k)
=-29/2