A relation is a set of ordered pairs with of x and y coordinates. You can look at a relation and determine its domain and range. Let's say you're working with the following relation: {(2, –3), (4, 6), (3, –1), (6, 6), (2, 3)}., To find the range of the relation, simply write down all of the y-coordinates of each ordered pair: {-3, 6, -1, 6, 3}., You'll notice that you have listed "6" two times. Take it out so that you are left with {-3, -1, 6, 3}., Now, reorder the numbers in the set so that you're moving from the smallest to the largest, and you have your range. The range of the relation {(2, –3), (4, 6), (3, –1), (6, 6), (2, 3)} is {-3,-1, 3, 6}. You're all done., For a relation to be a function, every time you put in one number of an x coordinate, the y coordinate has to be the same. For example, the relation {(2, 3) (2, 4) (6, 9)} is not a function, because when you put in 2 as an x the first time, you got a 3, but the second time you put in a 2, you got a four. For a relation to be a function, if you put in the same input, you should always get the same output. If you put in a -7, you should get the same y coordinate (whatever it may be) every single time.
Write down the relation.
List the y-coordinates of the relation.
Remove any duplicate coordinates so that you only have one of each y-coordinate.
Write the range of the relation in ascending order.
Make sure that the relation is a function.
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