18. golf luis and three friends went golfing. two of the friends rented clubs for $6 each. the total cost of the rented
clubs and the green fees for each person was $76. what was the cost of the green fees for each person? define a
variable, write an equation, and solve the problem.

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)