\[\left\{ \begin{matrix}
2a - 3b = 1\ \ | \cdot ( - 2) \\
4a + 2b = 3\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\
\end{matrix} \right.\ \text{\ \ \ \ \ }\]
\[\left\{ \begin{matrix}
- 4a + 6b = - 2\ \ (1) \\
4a + 2b = 3\ \ \ \ \ \ \ \ \ (2) \\
\end{matrix} \right.\ \]
\[(1) + (2) \Longrightarrow 8b = 1\]
\[\left\{ \begin{matrix}
8b = 1\ \ \ \ \ \ \ \ \ \ \\
2a - 3b = 1 \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix}
8b = 1\ \ \ \ \ \ \ \ \ \ \ \\
2a = 1 + 3b \\
\end{matrix} \right.\ \]