
\[\left\{ \begin{matrix}
3x - by = 12 \\
ax + 2y = 14 \\
\end{matrix} \right.\ \]
\[\left\{ \begin{matrix}
- 6 - 3b = 12 \\
- 2a + 6 = 14 \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix}
- 3b = 18 \\
- 2a = 8 \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix}
b = - 6 \\
a = - 4 \\
\end{matrix} \right.\ \]
\[Ответ:a = - 4;\ \ b = - 6.\]