PLEASE HELP I NEED HELP ;(

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)

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

Type the correct answer in each box, round your answers to the nearest integer 20 25 30 in the figure, the perimeter of hexagon abcdef is approximately w units, and its area is square units