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