Step-by-step explanation:
We are given a parabola which opens downwards as shown in the question.
To determine the intervals over the graph/function increases and decreases, we will need to study carefully the movement of the graph along the y-axis. As the graph rises along the y-axis, the corresponding x-values of the increasing region will be our intervals. The same procedure will be used to determine the interval of decrease.
Let us now study the movements of the curve;
Notice that the graph rises and reaches a maximum at the point where;
![x=3](https://img.qammunity.org/2023/formulas/mathematics/high-school/tu78xmfzid4zbk5fl1tm8vw66ibi0yce1h.png)
This means it rises from all x values less than 3 and does not rise beyond 3. Therefore;
![Increase:x<3](https://img.qammunity.org/2023/formulas/mathematics/college/4bejtnt2mbyo9x3xqhpmurgpdr2g1jzo0s.png)
After that it begins to fall continuously. That means the graph decreases at every x value after 3, that is;
![Decrease:x>3](https://img.qammunity.org/2023/formulas/mathematics/college/kmjlltehj6enekfui95ggytrkj0ajjuuk2.png)
Therefore,
ANSWER:
![Increase\text{ }x<3\text{ and }Decrease\text{ }x>3](https://img.qammunity.org/2023/formulas/mathematics/college/dmnnbete5vca0e5yv5vp8l27c27fmjhq3q.png)