Answer
$2t^2+6t-11$
Work Step by Step
Removing the grouping symbols and then combining like terms, the given expression, $
(3t^2-2t-5)-(t^2-8t+6)
,$ simplifies to
\begin{array}{l}
3t^2-2t-5-t^2+8t-6
\\\\=
(3t^2-t^2)+(-2t+8t)+(-5-6)
\\\\=
2t^2+6t-11
\end{array}