Solving Quadratic Equations by Using the Quadratic FormulaYou can use the quadratic formula to solve any quadratic equation involving any variable.
The Quadratic Formula
The solutions of a quadratic equation in the form ax2 + bx + c = 0, where a 0, are given by the formula
Use the quadratic formula to solve x2 - 2x - 5 = 0.
In the equation x2 - 2x - 5 = 0, a = 1, b = -2, and c = -5.
Substitute these values into the quadratic formula.
The solutions are approximately 3.45 and -1.45.