The problem asks to determine the domain on which the function is decreasing, based on the provided graph. Here's the solution:

Observations:

1. The graph is a parabola opening downward, which implies the function increases to a maximum point and then decreases.
2. The vertex is the maximum point, which occurs at $x = 8$ based on the graph.
3. The function is decreasing for values of $x$ to the right of the vertex ($x > 8$).

Decreasing Interval:

• The function decreases for $x \in (8, 16]$. This is because the graph slopes downward in this range.

Final Answer:

The domain where the function is decreasing is: $(8, 16]$

Would you like a detailed explanation of any steps or have questions about intervals?

Related Questions:

1. How do you find the vertex of a parabola from its graph?
2. What is the difference between increasing and decreasing intervals?
3. How do you determine the domain and range of a quadratic function?
4. Why does the parabola open downward in this case?
5. Can there be more than one decreasing interval for non-parabolic functions?

Tip:

To identify intervals of increase or decrease, focus on the slope of the graph—whether it moves upward or downward as $x$ increases.