I see that you've uploaded an image of a graph with a few questions related to it. Let's go through the tasks step by step:

a. The domain of the function:

The domain of a function refers to the set of all possible input values (x-values) that the function can accept. By observing the graph, we can determine where the function starts and ends along the x-axis. From the graph, it appears that the function is defined for $x$-values starting from 0 and extending to 20.

Therefore, the domain in interval notation would be: $\text{Domain: } [0, 20]$

Let me know if you'd like further details or assistance with the other parts of the problem. Would you like to continue with parts b, c, d, and e?

Here are some related questions to deepen your understanding:

1. How do you determine the domain of a function from a graph?
2. How do you determine the range of a function from a graph?
3. What is an intercept, and how can you find the intercepts from a graph?
4. How do you calculate the value of the function at a specific point (e.g., $f(9)$)?
5. How can you recognize a function's behavior if it approaches certain values on the graph?

Tip: When identifying the domain from a graph, pay attention to where the function begins and ends along the x-axis, noting any restrictions like asymptotes or gaps.