Find max height of ball: http://youtu.be/3PfiCtfmJA8
This video uses the vertex point of a parabola to find the maximum height of ball thrown in the air given its initial speed.
Find 2 numbers with minimum product: http://youtu.be/Qs_WqhoVBDI
Find 2 numbers whose difference is 6 and whose product is as small as possible. This is done using a quadratic equation and the vertex point.