Simplify each of the expressions below by combining like terms.
\begin{tabular}{|l|l|l|}
\hline 4.
$18+21 r-4 r+19 n-3$ & \multicolumn{2}{|c|}{5.
$-x+6 y-9 x-2 y-4 y$} \\
\hline 7.
$-4 \frac{1}{2} x+15+\frac{7}{2} x-23$ & 8.
$4 a-7.5 b+9 b-2.1 a$ & \\
\hline \multicolumn{2}{|c|}{\multirow{2}{*}{\begin{tabular}{l}
10. Simplify an expression for the perimeter of the rectangle.
$24.6 x-10.4$
$\square$ $7 x+3.1$ \\
Perimeter: $\qquad$
\end{tabular}}} & 11. Marge s below. \\
\hline & & \\
\hline
\end{tabular}
Answer (1)
x − am o u t o f 3$ t i c k e t s y − am o u t o f 5$ t i c k e t s x + y = 145∣ ( − 3 ) 3 x + 5 y = 663 − 3 x − 3 y = − 435 3 x + 5 y = 663 2 y = 228 y = 114 x = 145 − y x = 31
