\[Страница\ 21.\]
\[\boxed{\mathbf{11.}}\]
\[D \subset B\]
\[D \subset C\]
\[D \subset A\]
\[B \subset A\]
\[C \subset A\]
\[E \subset A\]
\[\boxed{\mathbf{12.}}\]
\[\textbf{а)}\ \left\{ 2;4;6;8 \right\}\]
\[\textbf{б)}\ \left\{ 1;3;7;9 \right\}\]
\[\textbf{в)}\ \left\{ 3;6;9 \right\}.\]
\[\boxed{\mathbf{13.}}\]
\[\textbf{б)}\ \left\{ 10;20;30;40;50;60 \right\}.\]
\[\textbf{в)}\ \left\{ 5;15;25;35;45;55 \right\}.\]
\[\boxed{\mathbf{14.}}\]
\[P = \left\{ a;b;c \right\}.\]
\[\boxed{\mathbf{15.}}\]
\[\textbf{а)}\ A \cup B = \left\{ 1;2;7;10 \right\}\]
\[\textbf{б)}\ A \cup C = 1;2;7;4;10\}\ \ \]
\[\textbf{в)}\ B \cup C = \left\{ 1;2;4;7;10 \right\}\]
\[\textbf{г)}\ A \cap B = \left\{ 1;2;7 \right\}\]
\[\textbf{д)}\ A \cap C = \left\{ \varnothing \right\}\]
\[\textbf{е)}\ C \cap B = \left\{ 10 \right\}\]