Observe the graph, the coordinates x and y can be any real number, there is an infinite number of ordered pairs that can be graphed. All of them lie on the line shown.

Notice that every real number is the x - coordinate of some point on the line.

Also, every real number is the y - coordinate of some point on the line.

So, the domain and range are both all real numbers, and the relation is continuous.

There is no vertical line that contains more than one of the points.Therefore, the relation is a function.

The domain and range are both all real numbers, and the relation is a function.