\[\boxed{\text{447\ (447).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[\left\{ 1 \right\}\ \subset \left\{ 1,\ 2 \right\};\]
\[\left\{ 2 \right\}\ \subset \left\{ 1,\ 2 \right\};\]
\[\varnothing \subset \left\{ 1,\ 2 \right\};\]
\[\left\{ 1,2 \right\} \subset \left\{ 1,\ 2 \right\}.\]
\[\boxed{\text{447.}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ \lbrack 6;10\rbrack\]
\[x = \left\{ 6;8;9;10 \right\rbrack.\]
\[2)\ (8,3;12\rbrack\]
\[x = \left\{ 9;10;11;12 \right\}.\]
\[3)\ ( - 5;4)\]
\[x = \left\lbrack - 4; - 3; - 2; - 1;0;1;2;3 \right\}.\]