Usefulness of $\frac{ac}{b}<a-b+c$

Question

For $$a<b<0<c$$

I have a proof that shows that $$\frac{ac}{b}>a-b+c$$ But if $$a<0<b<c$$ Then $$\frac{ac}{b}<a-b+c$$

What I was wondering is how useful are these inequalities in these forms? Do they have any applications?