问题描述： 已知x/3=y/4=z/5,求3x+2y-5z/x+y+z的值RT, 1个回答 分类：综合 2014-11-02 问题解答： 我来补答 x/3=y/4=z/5=tx=3t y=4t z=5t代入:(3x+2y-5z)/(x+y+z)(3*3t+2*4t-5*5t)/(3t+4t+5t)=(-8t)/(12t)=-2/3 展开全文阅读
