a:b=7:8,2b:a=( ):( ),2b:3a=( ):( )

问题描述:

a:b=7:8,2b:a=( ):( ),2b:3a=( ):( )

a:b=7:8,两边同乘1/2,的a:2b=7:16,的2b:a=16:7,同理的2b:3a=16:21