3a/(a+b)=2/3 对吗?
2a+2b=9a
7a=2b
a/b=2/7
a/b=c/d=e/f=2,求(a+c+e)/(b+d+f)
a=2b,c=2d,e=2f
(2b+2d+2f)/(b+d+f)=2(b+d+f)/(b+d+f)=2