Need help with 7 and 8 please

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)

What are the solutions of the equation x4 + 6x2 + 5 = 0? use u substitution to solve.

Marion bought 14 packages of plastic frog and lizard fishing lures. she bought frog lures in packages of 4 and lizard lures in packages of 6 for a total of 72 lures. how many of each lure did marion buy?