Răspuns :
AUB= {3,4,5,6,7,8}
A-B={3,4}
AB={(3,5), (3,6), (3,7), (3 8), (4,5),(4,6), (4,7), (4,8), (5,5), (5,6), (5,7), (5,8)}
[tex]\it A=\{3,\ 4,\ 5\}\\ \\ B=\{5,\ 6,\ 7,\ 8\}\\ \\ A\cup B=\{3,\ 4,\ 5,\ 6,\ 7,\ 8\}\\ \\ A\cap B=\{5\}\\ \\ A\ -\ B=\{3,\ 4\}[/tex]