A relation is just a set of x and y coordinates. Let's say you're working with the following coordinates: {(1, 3), (2, 4), (5, 7)}

, They are: 1, 2, 5.
 D = {1, 2, 5}

, For a relation to be a function, every time you put in one numerical x coordinate, you should get the same y coordinate. So, if you put in 3 for x, you should always get 6 for y, and so on. The following relation is not a function because you get two different values of "y" for each value of "x": {(1, 4),(3, 5),(1, 5)}.
Write down the relation.
Write down the x coordinates.
State the domain.
Make sure the relation is a function.
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