Help! :,( I don’t know how to do this :( and I need a good grade

What's the difference between: x≥0 and nonnegative integer. ?

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)

Q1 how many whole numbers less than 1000 can be written as a product of 3 consecutive whole numbers? a)10 b)11 c)15 d)21 q2 how many whole numbers between 5000 and 6000 consist of four different digits that decrease from left to right? a)3 b)10 c)69 d)120