You can find all sorts of definitions for the domain and range, but in this example it is really straight forward. If you put - 5 into the function, you get -2. If you put 7 into the function, you get 6. Now just draw a line between the two end points.
The point at the left end of the domain is not included in the function, but the function includes the limits of its range. One such function is shown in the attachment.