Thanks CPhill, follow up question:
A ball travels on a parabolic path in which the height (in feet) is given by the expression -16t^2+32t+15, where t is the time after launch. What is the maximum height of the ball?
In the form ax^2 + bx + c.....the x coordinate of the max height occurs at
-b / [ 2a] = -32 / [ 2 (-16) ] = 1
So.....the max height is -16(1)^2 + 32(1) + 15 = 31 ft
Here's the graph : https://www.desmos.com/calculator/tp0ornpndr
+267 
