Răspuns:
Explicație pas cu pas:
A = {x I x ∈ N ; si 2 ≤ x < 7} => A = {2 ; 3 ; 4 ; 5 ; 6}
B = {x I x ∈ N ; si -3 ≤ x < 2} => B = {0 ; 1}
C = {x I x ∈ Z ; si -3 ≤ x < 2} => C = {-3 ; -2 ; -1 ; 0 ; 1}
D = {x I x ∈ N ; si 11 < x² ≤ 50} =>
3² = 9 ; 4² = 16 ; 5² = 25 ; 6² = 36 ; 7² = 49 ; 8² = 64
D = {4 ; 5 ; 6 ; 7}
E = {x I x ∈ Z ; si 12 ≤ x² ≤ 47} =>
(±4)² = 16 ; (±5)² = 25 ; (±6)² = 36
E = {-6 ; -5 ; -4 ; 4 ; 5 ; 6}
F = {x I x ∈ Z ; si 14 ≤ 3x² < 122} =>
14 ≤ 3x² < 122 <=> 14/3 ≤ x² < 122/3 <=> 4,(6) ≤ x² < 40,(6)
(±3)² = 9 ; (±4)² = 16 ; (±5)² = 25 ; (±6)² = 36 =>
F = { -6 ; -5 ; -4 ; -3 ; 3 ; 4 ; 5 ; 6}
