\[\left\{ \begin{matrix} 15x - 4y = 8 \\ - 3x + y = 1\ \ \\ \end{matrix} \right.\ \]
\[\left\{ \begin{matrix} y = 1 + 3x\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ 15x - 4 \cdot (1 + 3x) = 8 \\ \end{matrix} \right.\ \]
\[15x - 4 - 12x = 8\]
\[3x = 12\]
\[x = 4.\]
\[y = 1 + 3x = 1 + 12 = 13.\]
\[Ответ:(4;13).\]