In Problem 13, we see the graph beginning just after x = -2. There's no dot at x = -2, which means that the domain does not include x = -2. Following the graph to the right, we end up at x = 8 and see that the graph does include a dot at this end point. Thus, the domain includes x = 8. More generally, the domain here is (-2, 8]. Note how this domain describes the input values for which we have a graph. (Very important.)
The smallest y-value shown in the graph is -6. There's no upper limit to y. Thus, the range is [-6, infinity).
Problem 14
Notice that the graph does not touch either the x- or the y-axis, but that there is a graph in both quadrants I and II representing this function. Thus, the domain is (-infinity, 0) ∪ (0, infinity).
There is no graph below the x-axis, and the graph does not touch that axis. Therefore, the range is (0, infinity).
