The quadratic function P(t) = -40t^2 + 320t models the number of people in a shopping mall during the day. Where t is the time in hours.
How long is the mall opened for (in hours) during the day?

Ineed with number 17 i don’t get it at alll

Marquise has 200 meters of fencing to build a rectangular garden. the garden's area (in square meters) as a function of the garden's width w w (in meters) is modeled by: a ( w ) = − w 2 + 1 0 0 w a(w)=−w 2 +100w what side width will produce the maximum garden area? meters

If t8 = 4 and t12 = −2, find the first three terms of the arithmetic sequence.