Question

determine all intervals on which the graph of (f) is decreasing on the closed interval (-9,9).

Explanation:

Step1: Recall decreasing - function property

A function \(y = f(x)\) is decreasing when the slope of the tangent line is negative or when, as \(x\) increases, \(y\) decreases.

Step2: Analyze the graph

By observing the graph of \(y = f(x)\) on the interval \([-9,9]\), we look for parts where the curve is going down - hill.
We can see that the function \(f(x)\) is decreasing on the intervals \([-9,-3]\) and \([5,9]\).

Answer:

\([-9,-3]\) and \([5,9]\)