Question 147162
h= -16t^2+32t
The problem asks how long he was ABOVE 14 feet -- which is h (height).  Simply plug it into the equation and solve for t (time).
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h= -16t^2+32t
14 = -16t^2+32t
Move everything to the left side:
16t^2 - 32t + 14 = 0
Divide by throughout by 2:
8t^2 - 16t + 7 = 0
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Since you can't factor, you must use the quadratic equation:
*[invoke quadratic "x", 8, -16, 7 ]
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x has two solutions:
1.35355339059327, 0.646446609406726
The difference is the time he was above 14 feet:
1.35355339059327 - 0.646446609406726 = .0607 seconds