\[\left\{ \begin{matrix} 2x + 5y = 17\ \ \ \ | \cdot 3 \\ 3x + 8y = 28\ \ \ \ | \cdot 2 \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix} 6x + 15y = 51 \\ 6x + 16y = 56 \\ \end{matrix} - \right.\ \text{\ \ \ \ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix} y = 5\ \ \ \ \ \ \ \ \ \ \ \ \ \\ x = \frac{17 - 5y}{2} \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ }\]
\[\left\{ \begin{matrix} y = 5\ \ \ \\ x = - 4 \\ \end{matrix} \right.\ \]
\[Ответ:( - 4;5).\]