Someone please help me answer this!!

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)

What is 617.3 miles and each gallon of gas the car can travel 41 miles select a reasonable estimate of the number of gallons of gas karl used.

Two consecutive negative integers have a product of 30. what are the integers?