Increasing numbers of manatees ("sea sirens") have been killed by boats off a state's coast. The following graph shows the relationship between the number of boats registered in that state and manatees killed each year.

The regression curve shown is given by
f(x) = 3.51x2 − 30.22x + 81 manatee deaths (4.5 ≤ x ≤ 8.5)
where x is the number of boats (hundreds of thousands) registered in the state in a particular year and f(x) is the number of manatees killed by boats in the state that year.

Compute f '(8).

Question

Increasing numbers of manatees ("sea sirens") have been killed by boats off a state's coast. The following graph shows the relationship between the number of boats registered in that state and manatees killed each year.

The regression curve shown is given by
f(x) = 3.51x2 − 30.22x + 81 manatee deaths    (4.5 ≤ x ≤ 8.5)
where x is the number of boats (hundreds of thousands) registered in the state in a particular year and f(x) is the number of manatees killed by boats in the state that year.

Compute f '(8).