A bag contains 37 coins consisting of only dimes and quarters. To total amount of money in the bag is $6.85. Which system of
equations
can be used to determine the number of quarters, 9,
and the number of dimes, d , in the bag?

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)