Write the following intervals in set-builder form

Write the following intervals in set-builder form:
(i) (-3, 0)
(ii) [6, 12]
(iii) (6, 12]
(iv) [-23, 5)
Answer
(i) (-3, 0) = {x: x ∈ R, -3 < x < 0}
(ii) [6, 12] = {x: x ∈ R, 6 ≤ x ≤ 12}
(iii) (6, 12] ={x: x ∈ R, 6 < x ≤ 12}
(iv) [-23, 5) = {x: x ∈ R, -23 ≤ x < 5}