Question 246760
Suppose Charlie O'Brian of the Braves hits a baseball straight upward at 150 ft/sec from a height of 5ft. 

Use the formula to determine how long does it takes the ball to return to the earth.
h(t) =-16t^2 + 150t + 5 (h in feet, t in seconds)
To find the time of impact, set h(t) = 0
-16t^2 + 150t + 5 = 0
*[invoke solve_quadratic_equation -16,150,5]

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Sub t for x, the solver uses x
Ignore the negative time.
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Estimate the maximum height reached by the ball 
That's at the vertex of the parabola.
t = -b/2a = -150/-32
t = 75/16 seconds
h(75/16) = -16*(75/16)^2 + 150*75/16 + 5
h = - 5625/16 + 11250/16 + 80/16
h = 5705/16 feet
h = 356.5625 feet exactly