Simple rearrangement

Question

I am not good at identifying simple things like the fact that this:

$\frac{n(n+1)+2(n+1)}2$ can be rearranged to $\frac{(n+1)(n+2)}2$

But why and how?

Sorry for this completely basic question but it's really difficult for me.

Answer 1

Hint : Factor out $n+1$ in the numerator.