exercitiile 9 si 10 va rog

9.
x€N
x=?
{2;3;x;9} = {2;3;7;9}
=> x=7
10. {-2,-1,x} - submultime a {-3,-2,-1,0,1,2,3}
x = ?
x€ {-3,-2,-1,0,1,2,3}/{-2,-1}
x€{-3,0,1,2,3}
Submultimile formate sunt:
{-3,-2,-1}, {-2,-1,0}, {-2,-1,1}, {-2,-1,2}, {-2,-1,3}