已知2a=3b=5c,则a+b-c/a-b+c=

问题描述:

已知2a=3b=5c,则a+b-c/a-b+c=

2a=3b=5c
所以b=2a/3,c=2a/5
所以原式=(a+2a/3-2a/5)/(a-2a/3+2a/5)
=(19a/15)/(11a/15)
=19/11