Question 908390
A fireworks shell is shot straight up with an initial velocity of 80 feet per second. Its height s after t seconds is given by the equation 
s = 80t − 16t2.
 If the shell is designed to explode when it reaches its maximum height, how long after being fired, and at what height, will the fireworks appear in the sky?
Don't burden us with gibberish.
s = 80t − 16t2.  What is that?
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h(t) = 80t - 16t^2
Use ^ for exponents, Shift 6
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The max ht is the vertex of the parabola.
The vertex is at t = -b/2a = 80/32 = 2.5 seconds
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 t = 2.5 seconds
h(2.5) = 200 - 100 = 100 feet
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don't waste your time and mine with this
time=_______ sec
height=_________ft