\[\boxed{\mathbf{1428}\mathbf{.}}\]
\[1)\ \left\{ \begin{matrix} \sqrt{x} + \sqrt{y} = 16 \\ \sqrt{x} - \sqrt{y} = 2\ \ \ \\ \end{matrix} \right.\ \ ( + )\ \ \ \]
\[\left\{ \begin{matrix} \sqrt{x} + \sqrt{y} = 16 \\ y = \left( \sqrt{x} - 2 \right)^{2} \\ \end{matrix} \right.\ \]
\[\sqrt{x} + \sqrt{x} + \sqrt{y} - \sqrt{y} = 16 + 2\]
\[2\sqrt{x} = 18\]
\[\sqrt{x} = 9\]
\[x = 81;\]
\[y = (9 - 2)^{2} = 7^{2} = 49.\]
\[Ответ:\ \ (81;\ 49).\]
\[2)\ \left\{ \begin{matrix} \sqrt{x} - \sqrt{y} = 1\ \ \\ \sqrt{x} + \sqrt{y} = 19 \\ \end{matrix} \right.\ \ ( + )\ \ \]
\[\left\{ \begin{matrix} y = \left( \sqrt{x} - 1 \right)^{2} \\ \sqrt{x} + \sqrt{y} = 19\ \\ \end{matrix} \right.\ \]
\[\sqrt{x} + \sqrt{x} - \sqrt{y} + \sqrt{y} = 1 + 19\]
\[2\sqrt{x} = 20\]
\[\sqrt{x} = 10\]
\[x = 100;\]
\[y = (10 - 1)^{2} = 9^{2} = 81.\]
\[Ответ:\ \ (100;\ 81).\]