**Domain of a Relation**

The **domain of a relation** is the set of first coordinates or x-values in a given set of ordered pairs.

For example, what is the domain of the set of ordered pairs below?

{(1,4), (5, 0), (-3, 1), (0, 4), (8, 7)}

The answer is

Domain: {1, 5, -3, 0, 8}