PLEASE HELP ME. I know I ask a lot, but I don’t know what I should come up with

Fractions can be added and subtracted only if they're fractions. a. like b. proper c. improper d. unlike

If eh = hg and hg=16, find the diameter of k

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)