All you have to do is find the slope of the graph.
1) Pick 2 points: (8,9) and (16,18) for example 2) Use the slope formula (y2-y1)/(x2-x1) 3) Once you know the slope, you know how much the graph will rise for each x-unit. Find the x distance between 24 and the new point (36), and use can calculate how high the y value should be