Extra #2

Recall from the domain and range sections that the domain is the set of all first numbers (x values), and the range is the set of all second numbers (y values). When we are given ordered pairs, mapping diagrams, or tables, it is really easy to pick out the domain and range. By simply looking at the diagrams below, we can easily record the domain and range.

However, sometimes we are asked to identify the domain and range when only a graph is supplied. To find the domain from a graph, look to see how far the line goes from left to right. In the example below, the left-most point is 1 and the right-most point is 5 on the x-axis. Therefore, the domain is all x-values from 1 to 5. This can be written with inequalities as 1 ≤ x ≤ 5.

To find the range from a graph, look to see how far the line goes up and down. In the example below, the lowest point is 3, and the highest point is 4. Therefore, the range is all y-values from 3 to 4. This can be written with inequalities as 3 ≤ y ≤ 4.