Question

FIE MULȚIMEA A={2,3,5,8,9} B={6,7,8,9,11} C={1,2,3,6,7}
A intersectat B
B-C {?}
A reunit C
A reunit (B-C)
(A reunit B)intersectat cu C
(A-C) reunit ( B-A)
A intersectat B intersectat C

Answer 1

A intersectat cu B ={8,9} B-C={8,9,11} A reunit cu C ={1,2,3,5,6,7,8,9} A reunit cu (B-C) ={2,3,5,8,9,11} (A reunit cu B) intersectat cu C ={2,3,6,7} (A-C) reunit cu (B-A) ={5,8,9,6,7,11} A intersectat cu B intersectat cu C =multime vidă

Answer 2

A={2,3,5,8,9} B={6,7,8,9,11} C={1,2,3,6,7} 1. A intersecat cu B={8,9,}

2. B-C={8,9,11}

3. A reunit cu C={2,3,5,8,9,1,6,7}={1,2,3,5,6,7,8,9}

4. A reunit cu B-C={2,3,5,8,9,11}

5. (A reunit B)intersectat cu C 
 dar (A reunit B)={2,3,5,8,9,6,7,11} si C={1,2,3,6,7}  deci
(A reunit B)intersectat cu C  ={2,3,6,7}

6.(A-C) reunit ( B-A) 
  .(A-C)={5,8,9,1,}  reunit cu (B-A)
B-A={6,7,11}  deci  (A-C) reunit ( B-A) 
  .(A-C)={5,8,9}  reunit cu (B-A)={6,7,11}={5,8,9,6,7,11}

7.A intersectat B intersectat C
A intersectat B ={8,9} (vezi pct 1) deci
{8,9}intersectat cu C={2,3}  A intersecta cu B intersecat cu C=multimea vida