Intermediate Algebra, Chapter 2, Cumulative Exercises, Section Cumulative Exercises, Problem 18

Simplify the expression $-7r + 5 - 13r + 12$



$
\begin{equation}
\begin{aligned}
-7r + 5 - 13r + 12 &= -7r - 13r + 5 + 12
&& \text{Use the Commutative Property of addition to regroup terms}\\
\\
&= -20r + 17
&& \text{Combine like terms}
\end{aligned}
\end{equation}
$