Question

Ajutoor va roog!
Fie multimile A= { x| x∈ N, 7 ≤ 5x + 2 ≤ 17} si B= { y | y ∈ N cu steluta sus , y < 3}
Calculati :
A U B, A U dar intors B , A - B, B - A

Answer 1

A={x | x∈N, 7≤5x+2≤17}
B={y | y∈N*, y<3}
7≤5x+2≤17 |-2
5≤5x≤15 |:5
1≤x≤3
A={1; 2; 3}
B={1; 2}
A∪B={1; 2; 3}=A (ce e in A sau in B)
A∩B={1; 2}=B (ce e si in A si in B)
A-B={3} (ce e in A si nu e in B)
B-A=∅ (ce e in B si nu e in A)