Use the graph below to determine a1 and d for the sequence.

A) a1 = −7; d = 10
B) a1 = −7; d = −10
C) a1 = 1; d = 10
D) a1 = 1; d = −10

Part A.

f(x) = 80.8

Part B.

x = 79

Part C.

Math class > Science class

Step-by-step explanation:

Using the function,

f(x) = .9x + 79

[x] is the # (number) of tests taken for math class. And in the question for Part A. it is said after completing test 2, this could be implying that what would there avg. be after taking 2 (two) tests. So, subsitute 2 into [x]

f(x)  = .9(2) + 79

f(x) = 1.8 + 79

f(x) = 80.8 <- This is the avg. for the math class

Part B.

From the table provided, after taking two tests, th avg. was 79, this can also be verified form the fact that it is shown:

x | g(x)

1 | 78

2 | 79 <- This is the avg. for science class.

3 | 80

Part C.

The class with the higher acg after completing test 4 would be the math class, because if you used the functiona nd subsituted 4 into [x], you would get: 82.6

While for the graph the next # (number) would be

4 | 81