1 The quadratic crosses the x axis in 2 different places
2 The quadratic has 2 different solutions.
3 The x value of the minimum or maximum is 1/2 way between these 2 solutions.
4 The y value of the minimum or maximum is found by substituting the x value into the original quadratic. (You can't really tell this from the discriminate, but it is an inferred property).
