The graph is showing the slope of the line
To do this you have to do rise over run, going from one dot to the other
It helps to remember that you have to get out your seat before you can walk
Therefore on graph three you start at the dot that's at the coordinates ( 1, 1.25) and move up... when you go up 1.50 units you then go over 2 units, therefore the slope of #3 is 1.50/2
You do the same for #6 however from my laptop screen the lines are a bit hard to see, but just follow the same steps ^
*Another thing to remember is that the slope on a graph will ALWAYS make a straight line, and the dot will always be on a line where the x, and y meet (if that make since) Also the slope NEVER changes... If the line is going up left to right, the slope will be positive. If its going down, right to left then it'll be negative*