已知:x/3=y/-4=z/7 求3x+y+z/y的值

问题描述:

已知:x/3=y/-4=z/7 求3x+y+z/y的值

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