The problem asks us to determine the intervals where the graph of the function $f$ is decreasing.

From the image, we can identify the intervals where the graph of $f$ is decreasing by observing the segments of the graph that are sloping downwards (moving from left to right).

Here are the decreasing intervals:

1. The graph decreases from approximately $x = -3$ to $x = -1$.
2. It decreases again from approximately $x = 1$ to $x = 3$.

Thus, the intervals where the graph of $f$ is decreasing are: $(-3, -1) \cup (1, 3)$

Would you like further details on how to interpret the graph or analyze other properties?

Here are five related questions to deepen your understanding:

1. What are the intervals where the graph of $f$ is increasing?
2. Can you identify the local maxima and minima on this graph?
3. How can you determine the concavity of the graph?
4. What is the significance of the x-intercepts in the context of this graph