Question 720438
    During practice, a softball pitcher throws a ball whose height can be modeled by the equation h=-16t^2+24t+1, where h=height in feet and t=time in seconds. How long does it take for the ball to reach a height of 6 feet?
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Set h to 6 and solve for t:
h=-16t^2+24t+1
6=-16t^2+24t+1
0 = -16t^2+24t-5
0 = 16t^2-24t+5
solve the above using the "quadratic formula" which yields:
t = {0.25, 1.25}
The ball reaches the height of 6 feet "on the way up" at 
0.25 seconds
and again, "on the way down" at
1.25 seconds
.
Details of quadratic follows:
*[invoke quadratic "x", 16, -24, 5 ]