A pillow that usually costs $18 is marked down 25%. Which expressions can be used to find the new price of the pillow? Check all that apply. 18 – 0.25(18) 18 – 0.75(18) 0.25(18) 0.75(18) 18(0.25) + 18

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)