Correct. In vertex form $\displaystyle{y}={a}{{\left({x}-{h}\right)}}^{{2}}+{k}\usepackage{cmbright}\Huge\$ , the vertex of the parabola is given by $\displaystyle{\left({h},{k}\right)}\usepackage{cmbright}\Huge\$ . This means that the vertex of the parabola given by $\displaystyle{h}=-{16}{{\left({t}-{2}\right)}}^{{2}}+{139}\usepackage{cmbright}\Huge\$ is (2, 139), so the rocket takes 2 seconds to get to the maximum height (since “time” is plotted along the x-axis).