Question

Factorize:
a³ + a − 3a² − 3

Answer 1

We have:
$a^3+a-3a^2-3=\left(a^3-3a^2\right)+\left(a-3\right)$
$$\begin{gathered} =a^2\left(a-3\right)+1\left(a-3\right) \\ =\left(a-3\right)\left(a^2+1\right) \end{gathered}$$