Question

determine the domain on which the following function is decreasing.

Explanation:

Step1: Identify vertex of parabola

The vertex (minimum point) of the parabola is at $x=4$.

Step2: Find decreasing interval

A parabola opening upward decreases from $-\infty$ to its vertex x-value.

Answer:

$(-\infty, 4)$ or all real numbers less than 4