Quadratic Formula Proof / Roots of Quadratic Equations

Here I will show you the steps for deriving the quadratic formula from the equation of a parabola. It's not hard, just a little algebra gymnastics. Once you know how to do it you probably will never have to do it again, but as I always say, it's better to now how to derive something than to simply memorize the answer.
So there you go !

Téa, the 13 year old Salman Khan, teaches and tutors math to middle school students.