How would you write {9, 10, 11, ....} in set builder notation?

How would you write {...-3, -2, -1, 0, 1, 2} in set builder notation?

Is this a true statement? 12 ∈ {9, 10, 11, ....} Why or why not?

Is this a true statement: 2 ∉ {9, 10, 11, ....}? Why or why not?

Is this a true statement: 9.5 ∈ {9, 10, 11, ....}? Why or why not?