For the chart the slope is 20 because for each increment of x, y increases by 20. We can write this in slope intercept form as y=20x
For the graph, calculate slope by finding rise over run. 70/2=35. In slope intercept form this is y=35x
Now plug in 12 for x in both equations
y=20(12) y=240
y=35(12)=420
Then subtract 420-240=180
Final answer: D