Question

Se A = {x ∈ Z; 2x + 3 = 15} e
B = {x ∈ Z; x ≥ 3 e x < 6}, então A ∩ B é:

a) {0}
b) ∅
c) {6}
d) {3, 4, 5, 6}

Answer 1

A = {x e Z; 2x + 3 = 15}
2x + 3 = 15
2x = 15-3
2x = 12
x = 12/2
x = 6
B = {x ∈ Z; x ≥ 3 e x < 6}
x ≥ 3 e x < 6 = {3,4,5,6}
A ∩ B = {6}
c) {6}