若x/3=y/4=z/7,求(3x-y+z)/(x-y+z)的值速度要过程

问题描述:

若x/3=y/4=z/7,求(3x-y+z)/(x-y+z)的值速度要过程

x/3=y/4=z/7=k
x=3k,y=4k,z=7k
(3x-y+z)/(x-y+z)
=(9k-4k+7k)/(3k-4k+7k)
=12/6
=2

设x/3=y/4=z/7=k(k≠0)
则x=3k,y=4k,z=7k
∴原式=(9k-4k+7k)/(3k-4k+7k)
=(12k)/(6k)
=2