A **quadratic equation** is a polynomial equation of degree 2. The generalized form is **ax ^{2} + bx + c = 0**. For example,

- 5
*x*^{2}+ 3*x*+ 4 = 0.

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