Determine whether each statement is true or false. Explain your answer.

1. Any set of ordered pairs is a function.
2. The perimeter of a square is a function of the length of a side
3. The set {(2, 4), (-2, 4), (3, 4)} is a function.
4. The set {(3, 1), (-2, 2), (3, 7)} is a function.
5. The set {(x, y) | x = 2y} is a function.