so hhmm notice the picture below
thus, the vertex of any parabola is
[tex]\bf \qquad \textit{vertex of a parabola}\\ \quad \\
\begin{array}{lccclll}
h=&-16t^2&+36t&+10\\
&\uparrow &\uparrow &\uparrow \\
&a&b&c
\end{array}\qquad
\left(-\cfrac{{{ b}}}{2{{ a}}}\quad ,\quad {{ c}}-\cfrac{{{ b}}^2}{4{{ a}}}\right)[/tex]
so, it reaches its maximum point at [tex]\bf -\cfrac{{{ b}}}{2{{ a}}}\quad seconds[/tex]
and the ball's' maximum height is [tex]\bf {{ c}}-\cfrac{{{ b}}^2}{4{{ a}}}\quad feet[/tex]
