<PRE><B>Question 87764</B>
The vertex of the parabola {{{y = ax^2 +bx +c}}} occurs at {{{x=-b/(2a) }}} .

Therefore, for your function {{{s(x) = -16x^2+200x + 4}}}, the vertex occurs at {{{x= -200/(2(-16) )= -200/-32=25/5 = 6.25 }}} seconds.


The maximum height is at {{{s(6.25) = 629 }}} feet.  By the way, I used a graphing calculator, with window:  x= [-2,14], y = [-100, 700].  It looks like this:

{{{graph( 300, 600, -2,14,-100,700, -16x^2+200x + 4) }}}


R^2  Retired from SCC
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