if you look at graph #3 and move your finger across the horizontal line moving to the right, going to positive two you'll see that there is a dot at exactly 2 1/2. so, you've got the point (2, 2 1/2)
Then, if you move your finger horizontally to the left, you'll get to -1 1/2. Then, moving your finger down you'll find a point at (-1 1/2, -4)
