Which of the following data sets represent a function?
{(2,3) , (3,1) , (2,-5)}
{(3,9) , (7,4) , (1,6)}
{(4,3) , (4,2) , (4,1)}
{(7,6) , (6,7) , (7,8)}

{(3,9) , (7,4) , (1,6)}  represents a function.

Step-by-step explanation:

A function must have only one x-value per y-value. There cannot be two or more x-values in a function with different y-values. All of the other options have two or more x-values that are the same.

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