(3 3/4)÷(−2 1/2) plz help me

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angle measure.

Alonso walked with his friend andy one day, and wanted to compare their speeds. alonso walked 3 miles in one hour, and andy walked 2 miles in 2 hours. complete the table to graph the relationship for each person.

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)