Incorrect. For $\displaystyle{f{{\left({x}\right)}}}={a}{{x}}^{{2}}+{b}{x}+{c}\usepackage{cmbright}\Huge\$ , the vertex is: $\displaystyle{\left(-\frac{{b}}{{{2}{a}}},{f{{\left(-\frac{{b}}{{{2}{a}}}\right)}}}\right)}\usepackage{cmbright}\Huge\$

Substitute the values $\displaystyle{a}=-{1}\usepackage{cmbright}\Huge\$ and $\displaystyle{b}={6}\usepackage{cmbright}\Huge\$ into the expression $\displaystyle-\frac{{b}}{{{2}{a}}}\usepackage{cmbright}\Huge\$ to find the x-coordinate. Then substitute the x-coordinate into $\displaystyle{f{{\left({x}\right)}}}\usepackage{cmbright}\Huge\$ to find the y-coordinate.