23.5 in expanded form

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)

Erin bought christmas cards for $2 each to send to her family and friends. which variable is the dependent variable?

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.