\[\boxed{\mathbf{887\ (}\mathbf{н}\mathbf{)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[A = \left\{ 11,\ - 7,\ 19 \right\}\]
\[A_{1} = \left\{ 11 \right\};\ \ A_{2} = \left\{ - 7 \right\};\ \ \ \]
\[\ A_{3} = \left\{ 19 \right\}.\]