\[\left( 2a_{1} + d(n - 1) \right)n = 8n^{2} - 10n\]
\[Пусть\ n = 11:\]
\[\left( 2a_{1} + 10d \right) \cdot 11 = 8 \cdot 121 - 110\]
\[22a_{1} + 110d - 858 = 0\ \ \ \ \ \ \ |\ :22\]
\[\left\{ \begin{matrix} a_{1} + 5d - 39 = 0 \\ 2a_{1} + d = 6\ \ \ \ \ \ \ \ \ \ \\ \end{matrix}\text{\ \ \ \ \ \ \ \ } \right.\ \]
\[\left\{ \begin{matrix} a_{1} + 5 \cdot \left( 6 - 2a_{1} \right) - 39 = 0 \\ d = 6 - 2a_{1}\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ } \\ \end{matrix} \right.\ \ \]
\[\left\{ \begin{matrix} a_{1} + 30 - 10a_{1} - 39 = 0 \\ d = 6 - 2a_{1}\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ } \\ \end{matrix}\text{\ \ \ \ \ \ \ \ \ \ } \right.\ \]
\[\left\{ \begin{matrix} - 9a_{1} = 9\ \ \ \ \ \\ d = 6 - 2a_{1} \\ \end{matrix}\text{\ \ \ \ \ \ \ \ }\left\{ \begin{matrix} a_{1} = - 1 \\ d = 8\ \ \ \ \ \\ \end{matrix} \right.\ \right.\ \]
\[Ответ:\ \ a_{1} = - 1;\ \ d = 8.\]