Which set of ordered pairs represents a function?

{(2, –2), (1, 5), (–2, 2), (1, –3), (8, –1)}
{(3, –1), (7, 1), (–6, –1), (9, 1), (2, –1)}
{(6, 8), (5, 2), (–2, –5), (1, –3), (–2, 9)}
{(–3, 1), (6, 3), (–3, 2), (–3, –3), (1, –1)}

Question

Which set of ordered pairs represents a function?

{(2, –2), (1, 5), (–2, 2), (1, –3), (8, –1)}
{(3, –1), (7, 1), (–6, –1), (9, 1), (2, –1)}
{(6, 8), (5, 2), (–2, –5), (1, –3), (–2, 9)}
{(–3, 1), (6, 3), (–3, 2), (–3, –3), (1, –1)}

anonymous · Answer

whats the answer

anonymous · Answer

are you sure

mathmale · Answer

Please explain what you are looking for as you try to decide whether or not this is a function.  The more you know about "functions" and their definition, the easier it will be to answer this question.

mathmale · Answer

How would I recognize you?

Once you've answered that, tell me, please, how I could recognize a function, as well as how I couldf recognize a non-function.