\[\boxed{\mathbf{818\ (818)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\textbf{а)}\ A = \left\{ 2;3;8 \right\};\ \ \ B = \left\{ 2;3;8;11 \right\};\ \ \ C = \left\{ 5;11 \right\}.\]
\[1)\ A \cap B = \left\{ 2;3;8 \right\}\]
\[A \cap C = \varnothing\]
\[B \cap C = \left\{ 11 \right\}.\]
\[2)\ A \cup B = \left\{ 2;3;8;11 \right\}\]
\[A \cup C = \left\{ 2;3;5;8;11 \right\}\]
\[B \cup C = \left\{ 2;3;5;8;11 \right\}.\]
\[\textbf{б)}\ K = \left\{ a;b;c \right\};\ \ \ M = \left\{ x;y \right\};\ \ \ P = \left\{ b;c;x \right\}.\]
\[1)\ K \cap M = \varnothing\]
\[M \cap P = \left\{ x \right\}\]
\[K \cap P = \left\{ b;c \right\}.\]
\[2)\ K \cup M = \left\{ a;b;c;x;y \right\}\]
\[M \cup P = \left\{ b;c;x;y \right\}\]
\[K \cup P = \left\{ a;b;c;x \right\}\]