Incorrect. Factor out the 3 so that $\displaystyle{y}={3}{\left({{x}}^{{2}}-{8}{x}\right)}-{5}\usepackage{cmbright}\Huge\$ . Now, add c to the right and 3c to the left so that $\displaystyle{y}+{3}{c}={3}{\left({{x}}^{{2}}-{8}{x}+{c}\right)}-{5}\usepackage{cmbright}\Huge\$ . What value for c makes $\displaystyle{{x}}^{{2}}-{8}{x}+{c}\usepackage{cmbright}\Huge\$ a perfect square trinomial? Find c and write the completed square as a binomial squared. Then, solve for y to get your equation in vertex form, $\displaystyle{y}={a}{{\left({x}-{h}\right)}}^{{2}}+{k}\usepackage{cmbright}\Huge\$ . The point $\displaystyle{\left({h},{k}\right)}\usepackage{cmbright}\Huge\$ will be the vertex.