Can y= 4x^2 + 12x + 9  be factored? If so what are the factors ?

$\textcolor{g r e e n}{{\left(2 x + 3\right)}^{2} = \left(2 x + 3\right) \left(2 x + 3\right)}$
but trying out factors of $4$ together with factors of $9$ has this solution fairly quickly.