Answer
$2012$
Work Step by Step
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.
$\frac{2008+2016}{2}=2012$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.