Camille is attending a fundraiser. she pays for her admission and buys raffle tickets for $5 each. if she buys 10 raffle tickets, then she would spend a total of $135 at the fundraiser. the number s of dollars camille spends at the fundraiser is a function of r, the number of raffle tickets she buys. write the function's formula.

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 0 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)