Question

(c) What is the average rate of change of f(x)=x² - 6x + 8 from 5 to 9?

Answer 1

f(9) = 9^2 - 6(9) + 8 = 81 - 54 + 8 = 35

f(5) = 5^2 - 6(5) + 8 = 25 - 30 + 8 = 3

the average rate of change is simply the slope of the line between those two points: (9,35) and (5,3)

m = (35-3)/(9-5)

= 32/4

= 8