Question

Tìm tất cả các tập hợp X sao cho: \(X\subset\left\{1;2;3;4\right\}\)

Answer 1

\(\varnothing;\left\{1\right\};\left\{2\right\};\left\{3\right\};\left\{4\right\};\left\{1;2\right\};\left\{1;3\right\};\left\{1;4\right\};\left\{2;3\right\};\left\{2;4\right\};\left\{3;4\right\}\)

\(\left\{1;2;3\right\};\left\{1;2;4\right\};\left\{2;3;4\right\};\left\{1;3;4\right\};\left\{1;2;3;4\right\}\)