To determine the domain of a function from the graph, identify the set of all the x-coordinates in the function’s graph.

a graph of a ray with an endpoint at (0, -2) and going up to the right is shown

In this example, the domain is x > 0 since 0 is the least x-value and the arrow indicates the line continues to the right.

To determine the range of a function from the graph, identify the set of all the y-coordinates in the function’s graph.

In this example, the range is y > -2 since -2 is the least y-value and the arrow indicates the line continues upward.