In order to get the slope for any graph, you can just take two points (x,y) and use the formula m = (y2 -- y1) / (x2 -- x1). For example, you can use the points (10,30) and (40,50) take the second y value and the first and subtract them from each other and divide that by the second x and the first x value. The answer should be 2/3 and this should work with any two points you choose.