Chapter 5 - Polynomials and Factoring - 5.4 Factoring Perfect-Square Trinomials and Differences of Squares - 5.4 Exercise Set - Page 333: 96

$2t^2+6t-11$

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}