Cole ordered four bags of salted potato chips three bags of sour cream and chive potato chips and two bags of barbecue potato chips cole finds the cost using the expression for 6+ 3x plus 2x where x is the cost of one bag of chips explain a more efficient way to use an expression to work out the cost

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)