posted by please help .
A ball is thrown into the air with an upword velocity of 36 ft/s. Its hight H in feet after t seconds is given by the function h=-16t^2+36t+9. In how many seconds does the ball reach its maximum height? Round to the nearest hundredth if necessary. What is the balls maximum height
You want the vertex of this parabola.
the x of the vertex is -b/2a
= -36/-32 = 1.125 seconds
plug that in
h = - 16(1.125)^2 + 36(1.125) + 9 = ....