# The Expanded form and the Quadratic Formula

Move the slider to change the values of parameters a, b and c.
What happens when the value of parameter a is zero?
What are the minimum and maximum number of roots for a quadratic?
What kind of quadratic expression results in "two repeated roots"?
How do we find the roots algebraically?

__The Quadratic formula__: (Tick both boxes in the applet) How is the Quadratic formula related to the roots? How is the Quadratic formula related to the axis of symmetry? What happens to the calculation for the Quadratic formula when there are "no real roots"?## Discover Resources

Download our apps here: