Where is the vertex of this quadratic graph? [br][br]How would you describe its position in terms of b?

The following silent video shows this construction.[br][list][*]When you add the point B=(b,0), a new parameter b will be created at the same time, in the form of a slider. You may then adjust the range and step of that slider. The value of b can be controlled by both the slider and the point B on the graph via dragging.[/*][*]Explore the symmetry of the graph, then use the perpendicular bisector of AB to locate the vertex. [/*][*]By finding the distance of the vertex from the axis, we can translate the graph to make a perfect square (or graphically completing a square). [/*][/list]