SAT OG 2道 实在郁闷了～if a,b,c,fare four nonzero numbers,then all of the following proportions are equivelent EXCEPTA a/b=b/c B f/c=b/aC c/a=f/bD a/c=b/fE af/bc=1/1为什么呢?

SAT OG 2道 实在郁闷了～
if a,b,c,fare four nonzero numbers,then all of the following proportions are equivelent EXCEPT
A a/b=b/c
B f/c=b/a
C c/a=f/b
D a/c=b/f
E af/bc=1/1
为什么呢?

BCDE都等价于bc=af
只有A不能推出这个

同学你能再发一遍吗？我电脑出了点毛病……真是对不起啊