Răspuns :
Din a 2 a relatie rezulta {4,5,6}⊂A SI {4,5,6}⊂B
Din a 3-a relatie=.>{1,2,3}⊂A si{1,2,3}⊄B
dECI a={1,2,3}u{4,5,6}={1,2,3,4,5,6}
dEOARECE {7,8}⊂AUB=>
{7,8}⊂B=>
B={4,5,6,}U{7,8}={4,5,6,7,8}
Din a 3-a relatie=.>{1,2,3}⊂A si{1,2,3}⊄B
dECI a={1,2,3}u{4,5,6}={1,2,3,4,5,6}
dEOARECE {7,8}⊂AUB=>
{7,8}⊂B=>
B={4,5,6,}U{7,8}={4,5,6,7,8}