若x/2=y/3=z/-5，求2x+y+3z/2x的值．
问题描述：
若
=x 2
=y 3
，求z -5
的值．2x+y+3z 2x
答
设
=x 2
=y 3
=k，则x=2k，y=3k，z=-5k；z -5
所以
=2x+y+3z 2x
=2×2k+3k+3×(-5) 2×2k
=-2．-8k 4k