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

$-t^4+2.5t^3-0.6t^2-9$
Removing the grouping symbols and then combining like terms, the given expression, $(t^3-0.3t^2-20)-(t^4-1.5t^3+0.3t^2-11) ,$ simplifies to \begin{array}{l} t^3-0.3t^2-20-t^4+1.5t^3-0.3t^2+11 \\\\= -t^4+(t^3+1.5t^3)+(-0.3t^2-0.3t^2)+(-20+11) \\\\= -t^4+2.5t^3-0.6t^2-9 .\end{array}