The range of the graph corresponds to the set of y-values the graph takes as it moves along the x-axis. From the image, we can see that the graph has a highest point at $y = 20$ and a lowest point at $y = -20$.

Thus, the range of the function is:

$[-20, 20]$

Let me know if you need further clarification or have any questions!

Here are some related questions:

1. How do you determine the domain of a graph?
2. What are the vertical line test and how does it determine whether a graph represents a function?
3. How can you determine if a graph has symmetry with respect to the y-axis?
4. How do you use the vertical line test for graphs with more than one curve?
5. What is the significance of intercepts in analyzing a graph?

Tip: To determine the domain of a function, identify the x-values that make the function undefined (for example, divisions by zero) or out of bounds.