Help me pls I don’t getvthis

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)

Which of the following pair(s) of circles have las a common external tangent? select all that apply. a and b a and c b and c

Jimmy can run 3.5 miles in 20 minutes. how far can ne run in one hour and ten minutes?