The solutions of some quadratic equations, (), are not rational, and cannot be obtained by factoring. For such equations, the most common method of solution is the quadratic formula.
Note: The quadratic formula can be used to solve ANY quadratic equation, even those that can be factored. Be sure you know this very useful formula!!!
The quadratic formula is derived from the quadratic equation by a process called "completing the square". Here is how it was developed: