When you look at the graph, you see that the line is in a U shape. We are trying to see what the value of g(x)=4. Since g is represented by the graph, the equation equals 4. The 4 in the equation is positive so you would look at the graph for a positive 4. There are 2 positive 4's on the graph; one on the x axis and one on the y axis. If you look at the U-shaped line, you see that it passes the 4 on the y axis. (the point -2,4 has the 4 as y and the point 2,4 has 4 as y). This makes the answer -2 and 2 because both the numbers have 4 as the y when you put them as points.
