Please help me what would the angle be subtracting them

Geometry paper. i don't know how to do the rest. questions 5. 8. 9. and 10.

Lorenzo ate 2/5 of his bag of almonds. his 4 friends ate equal shares of the remaining bag of almonds?

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)