a. The independent variable is r. The dependent variable is m.
b. The domain is the set of numbers used in the independent variable. You can rent 0 videos, or 1 video, or 2 videos, etc., up to the amount of money you have. If you rent 0 videos, you are left with m = 30 - 3r = 30 - 3(0) = 30 - 0 = 30 dollars. If you rent 10 videos, you will have m = 30 - 3(10) = 30 - 30 = 0 dollars left. The domain is {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}. The range is {0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30}. Both the domain and range are discrete.
c. I can't do it online.
