$\begin{array}{l}
6)\,\,\,\left\{ \begin{array}{l}
x + 3y = 13\\
2x + y = 6
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x = 13 - 3y\\
2.\left( {13 - 3y} \right) + y = 6
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
x = 13 - 3y\\
26 - 6y + y = 6
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x = 13 - 3y\\
- 5y = - 20
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
x = 13 - 3.4\\
y = 4
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x = 1\\
y = 4
\end{array} \right.\\
Vay\,\,\left( {x;y} \right) = \left( {1;4} \right)\\
9)\,\,\,\left\{ \begin{array}{l}
x + 5y = 22\\
2x + y = 9
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x = 22 - 5y\\
2.\left( {22 - 5y} \right) + y = 9
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
x = 22 - 5y\\
44 - 10y + y = 9
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x = 22 - 5y\\
- 9y = - 35
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
x = 22 - 5.\dfrac{{35}}{9}\\
y = \dfrac{{35}}{9}
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x = \dfrac{{23}}{9}\\
y = \dfrac{{35}}{9}
\end{array} \right.\\
Vay\,\,\left( {x;y} \right) = \left( {\dfrac{{23}}{9};\dfrac{{35}}{9}} \right).
\end{array}$
