A waterfall has a height of 1500 feet. A pebble is thrown upward from the top of the falls with an initial velocity of 20 feet per second. The height, h, of the pebble after t seconds is given by the equation h = -16t^2 + 20t +1500. How long after the pebble is thrown will it hit the ground? The pebble will hit the ground about [___] seconds after it is thrown.

(Simplify your answer. Round to one decimal place as needed.)

Find and simplify an expression for the area of five rows of x squares with side lengths of x centimeters .

Ascientist places 24 cells in a petri dish. she knows the cells grow at an exponential rate, doubling in number every hour. how long will it take (in hours) for there to be 1100 cells in the dish? time to 1100 cells: 5.51832530 hours how long will it take to reach 110 cells? time to 110 cells : 2.1963972 hours what is the average rate of change in the number of cells between 9 hours and 11 hours? average rate of change: cells per hour what is the instantaneous rate of change after 7 hours? instantaneous rate of change: cells per hour note: you can earn partial credit on this problem.

Which equation represents a line that passes through the point (9, -4) and has a slope of 3/5?