## Algebra and Trigonometry 10th Edition

$2012$
The vertex lies in the symmetry axis of the parabola. So, if $P(t_1)=P(t_2)$, in which $t_1\ne t_2$, then $t_1$ and $t_2$ are equidistant from the $t$ of the vertex. $\frac{2008+2016}{2}=2012$