Try changing the equation and the location of the parabola by moving the sldiers. Can you predict where the vertex of the parabola will be? Can you predict the axis of symmetry of your equation?
What does the a coefficient do to the curve? What does the c coefficient do to the curve? What does the b coefficient do to the curve? What is the equation of the axis of symmetry? What formula can you come up with to predict where the axis of symmetry will be?