How do I answer number 14?

Abee with velocity vector r'(t) starts out at (5, −5, −3) at t = 0 and flies around for 5 seconds. where is the bee located at time t = 5 if 5 0 r'(u)du = 0?

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)

Plz ( true - false) all triangles have interior angles whose measure sum to 90.