Slope = 8
Plug it in =
39 = 6 (8) + b
B = 9
So,
y = 8x + 9
Answer:
a5 =243 x (1/3)^(5-1) = 243x 1/81 =3
Explanation
a(n) = a(1) x r^(n-1)
y=4x+40
x represents the number of minutes
y is the total
40 because he already graded 40 papers, and 4x because that's how many phred grades times the number of minutes