Pani wants to buy 3 shirts and 2 new jeans. the cost of each shirt without the discount is 12$, and the cost of each pair of jeans is 19$ before the discount.

write and simplify an expression to find the amount pani pays if a $3 discount is applied to her total.

i don't understand this one plz

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)