If the slope is 3, it's actually 3/1 because of rise/run. So you find any point on the graph that's directly between two lines, like (-1,-5). Since the line is positive, you would go right one and up three. Then you see if that point is directly between two lines. The next point is (0, -2). If you did the same on the second graph, it wouldn't match up.
She would save 54.45 because addding them up individually before the plan would cost 184.49 and to find the difference all you have to do is subtract 184.49-129.99 and that would tell you how much she saved
