\[\begin{array}{l}
A = \left\{ {7; - 7;\,\,6;\,\,8; - 5} \right\}\\
a)\,\,\,6\,\,\,tap\,\,\,hop\,\,con\,\,cua\,\,A:\\
{A_1} = \emptyset & & & {A_2} = \left\{ 7 \right\} & & {A_3} = \left\{ { - 7} \right\}\\
{A_4} = \left\{ {6;\,\,8} \right\} & & {A_5} = \left\{ {7; - 5} \right\} & & {A_6} = \left\{ {7;\,\,6;\,\,8} \right\}\\
b)\,\,B = \left\{ {7; - 7;\,\,6; - 6;\,\,8; - 8;\,\,5;\, - 5} \right\}.
\end{array}\]
