What are the steps in order to correctly solve the equation 4x1/3 + 9 = 25
and what is the correct answer?

Me because some of question i don’t understand

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)

You buy 4 items that cost 2.69 14.45 8.05 13.95 what is the estimated total round to the nearest dollar