Quadratic equation
From Wikipedia, the free encyclopedia.

A quadratic equation is a polynomial equation of degree 2. The generalized form is ax² + bx + c = 0. For example,

5x² + 3x + 4 = 0.

The numbers 5, 3 and 4 here are called coefficients: 5 is the coefficient of x² and 3 is the coefficient of x.

A quadratic equation with real or complex coefficients has two complex roots (i.e., solutions), although the two roots may be equal. These roots can be computed using the quadratic formula.

See also: linear equation, cubic equation, quartic equation, quintic equation, fundamental theorem of algebra

The original article can be found at: http://en.wikipedia.org/wiki/Quadratic_equation.
All text is available under the terms of the GNU Free Documentation License.