Răspuns:
Explicație pas cu pas:
A = {x I x ∈ N ; ; x I 18 si 2x+3 ≤ 15}
2x + 3 ≤ 15 <=> 2x ≤ 15-3 <=> 2x ≤ 12 I :2 =>
x ≤ 6 ; x I 18 ; x ∈ N => x ∈{ 1 ; 2 ; 3 ; 6} =>
A = { 1 ; 2 ; 3 ; 6}
B = {x I x ∈ N ; x I 14 si 2x-1 < 19}
2x-1 < 19 <=> 2x < 19+1 <=> 2x < 20 I :2
x < 10 ; x I 14 ; x ∈ N => x ∈ { 1 ; 2 ; 7} =>
B = {1 ; 2 ; 7}
