PLEASE HELP Samuel collects seashells at the beach each summer. The function, f(x), summers. f(1)=15f(x)=f(x−1)+6
Complete the table to represent the number of seashells in the collection after the first four summers.

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)