Question

what is
a-b/ab +b-c/ bc + c-a/ac ?

Answer 1

Well, looking at the first term we have:
\[\frac{a-b}{ab} = \frac{a}{ab}-\frac{b}{ab} = \frac{1}{b}-\frac{1}{a}\]
seeing that we can do this to every term, the summation becomes:
\[\frac{1}{b}-\frac{1}{a}+\frac{1}{c}-\frac{1}{b}+\frac{1}{a}-\frac{1}{c}\]
in which everything will cancel out, and the answer is 0.