\[\boxed{\mathbf{719}.}\]
\[1)\ \left\{ \begin{matrix} 2^{x} + 2^{y} = 6 \\ 2^{x} - 2^{y} = 2 \\ \end{matrix} \right.\ \ ( + )\]
\[1)\ 2^{x} + 2^{x} + 2^{y} - 2^{y} = 6 + 2\]
\[2 \bullet 2^{x} = 8\]
\[2^{x} = 4\]
\[2^{x} = 2^{2}\]
\[x = 2.\]
\[2)\ 2^{2} - 2^{y} = 2\]
\[4 - 2^{y} = 2\]
\[2^{y} = 2\]
\[2^{y} = 2^{1}\ \]
\[y = 1.\]
\[Ответ:\ \ (2;1).\]
\[2)\ \left\{ \begin{matrix} 3^{x} + 5^{y} = 8\ \ \ \\ 3^{x} - 5^{y} = - 2 \\ \end{matrix} \right.\ \ ( + )\]
\[1)\ 3^{x} + 3^{x} + 5^{y} - 5^{y} = 8 - 2\]
\[2 \bullet 3^{x} = 6\]
\[3^{x} = 3\]
\[3^{x} = 3^{1}\]
\[x = 1.\]
\[2)\ 3^{1} + 5^{y} = 8\]
\[5^{y} = 8 - 3\]
\[5^{y} = 5\]
\[5^{y} = 5^{1}\ \]
\[y = 1.\]
\[Ответ:\ \ (1;1).\]