Answer:
Part A: To find the average test score in math after test 2, plug in x=2 into the function f(x). So, f(2) = 0.9*2 + 79 = 1.8 + 79 = 80.8
Part B: The average test score in science after completing test 2 is given directly by g(2), which is 79.
Part C: To find out which class had a higher average after test 4, we first need to calculate f(4) for the math class. f(4) = 0.9*4 + 79 = 3.6 + 79 = 82.6
For the science class, we can see a pattern where the average increases by 1 with each test. So, g(4) would be 81.
Therefore, the math class had a higher average after completing test 4.