Incorrect. Rewrite in standard form by adding $\displaystyle{12}{x}\usepackage{cmbright}\Huge\$ to both sides: $\displaystyle{{x}}^{{2}}+{12}{x}+{36}={0}\usepackage{cmbright}\Huge\$

Use the Quadratic Formula, $\displaystyle{x}=\frac{{-{b}\pm\sqrt{{{{b}}^{{2}}-{4}{a}{c}}}}}{{{2}{a}}}\usepackage{cmbright}\Huge\$ , with $\displaystyle{a}={1},{b}={12}\usepackage{cmbright}\Huge\$ , and $\displaystyle{c}={36}\usepackage{cmbright}\Huge\$ . The correct answer is $\displaystyle-{6}\usepackage{cmbright}\Huge\$ .