80 inches squared, I would assume based off of the other one.
Each one would be 5 minutes because 2 1/2 Times 4 = 10 minutes. You would have 20 minutes remaining so divide 20 by how many segments there are, which is 4 to get 5
I believe it is -2 because it doubles and the pattern of negative then positive requires a negative b
The independent variable is M, Miles.
This is because you can walk however miles without any effect. But calories depends on how much you walked. Make sense?