Which of the following sets represents a function?
{(3, 5), (-1, 7), (3, 9)}
{(1, 2), (3, 2), (5, 7)}
{(1, 2), (1, 4), (1, 6)}
The set {(3, 5), (-1, 7), (3, 9)} does not represent a function because it contains two pairs with the same x-value, 3.
The set {(1,2), (3,2), (5,7)} represents a function because each x-value is paired with exactly one y-value.
The set {(1,2), (1,4), (1,6)} does not represent a function because it contains three pairs with the same x-value, 1.