Adevarat sau fals:
A={0,1,2,3,4,5,6}
B={5,6,7,8,9}
C={3,6,9,12,15}


a) C apartine {x€N | x divide 3} ;
b) A apartine {x€N | 3<(cu talpa jos)2x + 1<(cu talpa jos)13}.​