Answer:
yes it is a rational function.
Step-by-step explanation:
You can easily find out by graphing the function and using the vertical line test. If a vertical line drawn anywhere on the graph (except at vertical asymptotes where values are undefined) intersects the graph at only one point, then the relation is a valid function.
(See attached for graph)
We can see that indeed a vertical line drawn at any point will cut the graph only at one point, hence it is a rational function.
