How do I factor the equation in answering this question?

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 are two numbers that add up to -9 and multiply to -10 best answer gets branliest and 100 extra points

Solve the equation 1. x-3/4=2 4/52. -1/3x-11= -20 3. -12+5/7x= -19