SOLUTION: Bob hits a cricket ball into the air. The height(in feet) of the ball at time t seconds is given by h(t)= -10.5t^2+66.3t+6. Find the maximum height the ball reaches and the time in

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Bob hits a cricket ball into the air. The height(in feet) of the ball at time t seconds is given by h(t)= -10.5t^2+66.3t+6. Find the maximum height the ball reaches and the time in      Log On


   

Question 861461: Bob hits a cricket ball into the air. The height(in feet) of the ball at time t seconds is given by h(t)= -10.5t^2+66.3t+6. Find the maximum height the ball reaches and the time in seconds when that maximum height occurs. I'm not looking for the answer but HOW to solve this as I can't find the formula.
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
h(t)= -10.5t^2+66.3t+6 is the formula.
Find the vertex
-b/2a=-66.3/-21=t
vertex | (3.15714, 110.659)
or set the first derivative to 0
0 = 66.3-21t to find t