## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$-t^2-12t+13$
Removing the grouping symbols, then the given expression, $(-9t+12)-(t^2+3t-1)$, is equivalent to \begin{array}{l} -9t+12-t^2-3t+1 .\end{array} By combining like terms, then \begin{array}{l} -t^2+(-9t-3t)+(12+1) \\\\= -t^2-12t+13 .\end{array}