Answer:
The answer to your question is (-5, ∞)
Explanation:
A curve decreases when it goes down from left to right.
A curve increases when it goes up from left to right.
In the graph, we notice that it goes down from -∞ to the vertex (-5, -6.5)
And it goes up from the vertex (-5, -6.5) to +∞.
So the answer is (-5, ∞)