Given the graph of a Piecewise Function, you can identify that it has three pieces. See the picture below:
By definition, the open circles indicates that that endpoint is not included in the interval of the function.
By definition, the Domain of a function is the set of all the input values (x-values) for which the function is defined.
In this case, you need to analyze each piece in order to determine its Domain:
1. Notice that piece 1 goes from:

To:

But -2 is not included. Therefore:

2. Notice that piece 2 goes from:

To:

But since its endpoints are not included:

3. Piece 3 goes from:

To:

Since the x-value 6 is not included:

Hence, the answer is:
- For the first piece from left to right:

- For the middle piece:

- For the third piece from left to right:
