# Math Help - Nonzero numbers? (587)

1. ## Nonzero numbers? Thanks to Jameson!

If a, b, c, and f are four nonzero numbers then all of the following proportions are equivalent EXCEPT

a) $\frac {a}{f} = \frac{b}{c}$

b) $\frac {f}{c} = \frac{b}{a}$

c) $\frac {c}{a} = \frac{f}{b}$

d) $\frac {a}{c} = \frac{b}{f}$

e) $\frac {af}{bc} = 1$

Can someone please show me the steps? Does nonzero numbers simply mean numbers that can't equal to zero?
Thanks in advance

2. I think there's a big chunk of the problem missing

3. Yes, non-zero simply means not 0.

Let's start by finding two which ARE equal. Look at D) and E).

Cross multiply C) and you get af=cb. Do you know how to cross multiply? Now for E) multiply everything by bc and you get af=cb. So, good we've found two that match and a true statement to compare others to. Cross multiply C) and you get... af=cb, good. B) do the same thing and we get ... af=cb, awesome.

Now for A), cross multiply and we get ac=bf. UH OH. Found the different one.