To determine the domain where the given function is decreasing, we need to look at the portion of the graph where the slope is negative, meaning the function is going down as you move from left to right.

From the graph provided:

• The function starts decreasing after reaching its peak (maximum value) and continues decreasing to the right.
• The peak occurs at $x = 3$.
• The function is decreasing from $x = 3$ onward, continuing downwards.

Conclusion:

The function is decreasing on the domain $(3, \infty)$.

Let me know if you'd like a more detailed explanation or further clarifications!

Related questions:

1. What does it mean for a function to be increasing on a domain?
2. How can you find the maximum or minimum points of a function from its graph?
3. What are the key differences between increasing and decreasing functions?
4. Can a function be increasing and decreasing at the same time on different intervals?
5. How would you express the interval where a function is increasing?

Tip:

To identify whether a function is increasing or decreasing, observe the slope of the tangent line on each interval. If it's positive, the function is increasing; if it's negative, the function is decreasing.