Question

determine the domain on which the following function is decreasing.

Explanation:

Step1: Identify peak of the curve

The function reaches its maximum at $x=4$.

Step2: Find decreasing interval

For $x > 4$, as $x$ increases, $y$ decreases, until $x=13$ (the right endpoint of the domain).

Answer:

The function is decreasing on the interval $(4, 13)$ or $4 < x < 13$