Furthermore, the quadratic formula also provides the axis of symmetry of the parabola. The x values found through the quadratic formula are roots of the quadratic equation that represent the x values where any parabola crosses the x-axis. Recall that the ± exists as a function of computing a square root, making both positive and negative roots solutions of the quadratic equation. Below is the quadratic formula, as well as its derivation.įrom this point, it is possible to complete the square using the relationship that:Ĭontinuing the derivation using this relationship: Only the use of the quadratic formula, as well as the basics of completing the square, will be discussed here (since the derivation of the formula involves completing the square). A quadratic equation can be solved in multiple ways, including factoring, using the quadratic formula, completing the square, or graphing.

For example, a cannot be 0, or the equation would be linear rather than quadratic. The numerals a, b, and c are coefficients of the equation, and they represent known numbers. Where x is an unknown, a is referred to as the quadratic coefficient, b the linear coefficient, and c the constant.

In algebra, a quadratic equation is any polynomial equation of the second degree with the following form: Fractional values such as 3/4 can be used.

Quadratic sequence formula