What is ghe square root of 68 divided by 70 multiplyed by 8 times 4 divided 5 multiplyed by 67 divded by 100 times xy divided by the square root 7 times x times m divided by the square root of 97. WILL GIVE BRAINLIEST

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)