# math

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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

• math -

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 = ....

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