Beginning Algebra With Applications, Chapter 2, Test, Section Test, Problem 2

Simplify $7x + 5y - 3x - 8y$

$
\begin{equation}
\begin{aligned}
&= 7x - 3x + 5y - 8y && \text{Use the Commutative Property of Addition}\\
\\
&= (7-3)x + (5-8) y && \text{Use the Distributive Property } ba+ca= (b+c)a\\
\\
&= 4x - 3y && \text{Subtract coefficient}
\end{aligned}
\end{equation}
$