It is C (2, 1) I think it is because they intersect
First you find how much weight it lost
500 - 350 = 150
Then, to find the mean change you divide the weight lost by the number of months
150 : 6 = 25
25 is the monthly change
(3,12)(5,20)
rate of change (slope) = (y2 - y1) / (x2 - x1)
slope = (20 - 12) / (5 - 3)
slope = 8/2 = 4 credits per course
