Question 915888
There are several ways to write the sets formally. Here are examples:


{0,3,6,9,12} = *[tex \large \{x: \, x \equiv 0 \pmod{3}, 0 \le x \le 12 \} ] (*[tex \large x \equiv 0 \pmod 3] means that x leaves a remainder of zero when divided by 3). An alternate way is *[tex \large \{x : \, x = 3k, k \in \{0,1,2,3,4 \} \}].


{-3,-2,-1,0,1,2,3} can be written as *[tex \large \{x: \, x \in \mathbb{Z}, |x| \le 3 \}] (all x such that x is an integer and |x| is less than or equal to 3)


{m,n,o,p} I don't really know of a nice way to state this in set-builder notation, other than *[tex \large \{ x: \, x \in \{m, n, o, p \} \}] which is correct but doesn't make much sense since it is much longer than writing {m,n,o,p}.