\[\boxed{\mathbf{1173\ (1165)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ mx = 20\]
\[x = \frac{20}{m} \Longrightarrow m = 1;2;4;5;10;20.\]
\[2)\ (m + 3)x = - 18\]
\[x = - \frac{18}{m + 3} \Longrightarrow m + 3 = - 18;\]
\[\ - 9;\ - 6;\ - 3;\ - 2;\ - 1 \Longrightarrow\]
\[\Longrightarrow m = - 21;\ - 12;\ - 9;\ - 6;\]
\[\ - 5;\ - 4.\]