С объяснинием пожалуйста

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)

Question 14 (1 point) larry deposits $15 a week into a savings account. his balance in his savings account grows by a constant percent rate.

What is the solution to the equation e3x=12? round your answer to the nearest hundredth