\[\left\{ \begin{matrix} 3^{\log_{3}x} - 2^{\log_{4}y} = 77\ \ \ \\ 3^{\log_{3}\sqrt{x}} + 2^{\log_{16}y} = 11 \\ \end{matrix} \right.\ \]
\[1)\ 3^{\log_{3}\sqrt{x}} + 2^{\log_{2}\sqrt[4]{y}} = 11\]
\[\sqrt{x} + \sqrt[4]{y} = 11\]
\[\sqrt{x} = 11 - \sqrt[4]{y}.\]
\[2)\ 3^{\log_{3}x} - 2^{\log_{2}\sqrt{y}} = 77\]
\[x - \sqrt{y} = 77\]
\[x = 77 + \sqrt{y}\]
\[\left( \sqrt{x} \right)^{2} = 77 + \sqrt{y}\]
\[121 - 22\sqrt[4]{y} + \sqrt{y} = 77 + \sqrt{y}\]
\[22\sqrt[4]{y} = 44\]
\[\sqrt[4]{y} = 2\]
\[y = 2^{4} = 16;\]
\[x = 77 + \sqrt{16} = 77 + 4 = 81.\]
\[Ответ:\ \ (81;\ 16).\]