\[\left\{ \begin{matrix} 9x - 30 - 10x + 10y = 3x + 4 \\ 5x - 34 + 18y + 24 = 20y\ \ \ \ \ \ \\ \end{matrix} \right.\ \]
\[\left\{ \begin{matrix} 10y - 4x = 34\ \ \ \ \ \ \ \ \ \ \\ - 2y + 5x = 10\ \ | \cdot 5 \\ \end{matrix} \right.\ \text{\ \ \ \ \ }\]
\[\left\{ \begin{matrix} 10y - 4x = 34\ \ \ \ \ \\ - 10y + 25x = 50 \\ \end{matrix} + \right.\ \text{\ \ \ \ \ }\]
\[\left\{ \begin{matrix} 21x = 84\ \ \ \ \ \ \\ y = \frac{34 + 4x}{10} \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix} x = 4 \\ y = 5 \\ \end{matrix} \right.\ \]
\[Ответ:(4;5).\]