13x+y=4 plz help i cant get it right lol

Josephine has a great garden with and area of 2x2 + x - 6 square feet

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)

Tom travels between the two mile markers shown and then finds his average speed in miles per hour. select the three equations that represent this situation.