## Online Course Discussion Forum

### Need help on II-A Number Theory 2.27

Re: Need help on II-A Number Theory 2.27

Since $n$ is odd, it must be that $a$ is odd and $b$ is even (or vice versa). Say then $a = 2k + 1$, and $b = 2l$ for some integers $k$ and $l$. What can you say about $n$ now?