Incorrect. If the polynomial can be factored, its factored form will be $\displaystyle{\left({a}+{r}\right)}{\left({a}+{s}\right)}\usepackage{cmbright}\Huge\$ where $\displaystyle{r}{s}=-{12}\usepackage{cmbright}\Huge\$ and $\displaystyle{r}+{s}={4}\usepackage{cmbright}\Huge\$ . Factor the polynomial and use the zero product property to solve for a.