Quadratic formula

What is quadratic formula?

The quadratic formula solves any quadratic equation of the form ax² + bx + c = 0: x = (−b ± √(b² − 4ac)) / 2a. Use it when factorising won't work cleanly. The discriminant b² − 4ac determines the number of real roots: positive → two distinct real roots; zero → one repeated root; negative → no real roots. GCSE Higher tier expects exact answers using surds.