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

Answer:

$[-9,-4]\cup[1,6]$

Explanation:

Step1: Recall increasing - graph property

A function $y = f(x)$ is increasing on an interval if, as $x$ increases, $y$ also increases. That is, for any $x_1,x_2$ in the interval with $x_1<x_2$, we have $f(x_1)<f(x_2)$.

Step2: Analyze the given graph

Looking at the graph of $y = f(x)$ on the closed - interval $[-9,9]$, we observe that the graph is rising (going up from left to right) on the intervals $[-9,-4]$ and $[1,6]$. On the interval $[-9,-4]$, as $x$ moves from $-9$ to $-4$, the $y$ - values of the function are increasing. Similarly, on the interval $[1,6]$, as $x$ moves from $1$ to $6$, the $y$ - values of the function are increasing.