\[\boxed{\mathbf{814\ (814)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[X = \left\{ a;b;c \right\}.\]
\[Подмножества\ X:\ \left\{ a \right\},\left\{ b \right\},\left\{ c \right\},\left\{ a;c \right\},\ \left\{ a;b \right\},\left\{ b;c \right\},\left\{ a;b;c \right\},\ \varnothing.\]
\[Итого:\ \ \ 8\ подмножеств.\]