\[ax = - 10;\ \ \ x - целое\ число;\]
\[x = - \frac{10}{a}\]
\[a = \{ - 1;\ \ 1;\ - 2;\ \ 2;\ - 5;\ \ \]
\[5;\ - 10;\ \ 10\}.\]
\[Ответ:\ a = \{ - 1;\ \ 1;\ - 2;\ \ 2;\ - 5;\ \ \]