Describing Domain and Range

To express the set of given $(x,y)$ ordered pairs in a table of values, we'll list all of the $x$-values in one column and all of the $y$-values in another column.

To graph an $(x,y)$ ordered pair, start by identifying the $x$- and $y$-coordinates on the axes. Then, trace along the grid lines to the point on which both coordinates lie. We'll do this for every ordered pair in the relation.

To show a relation of $(x,y)$ ordered pairs as a relation, list all of the unique $x$-values in one vertical list and all unique $y$-values in another vertical list. Then, use arrows to connect corresponding $x$- and $y$-values.

The domain of this relation is the set of all unique $x$-values and the range is the set of all unique $y$-values. $$\begin{array}{rl}D\text{: }& \{2,4,6,8\}\\ R\text{: }& \{1,2,3,4\}\end{array}$$