A complex quadratic polynomial is a quadratic polynomial whose coefficients are complex numbers.In mathematics, a quadratic polynomial or quadratic is a polynomial of degree two, also called second-order polynomial. That means the exponents of the polynomial's variables are no larger than 2. For example, x2 4x + 7 is a quadratic polynomial, while x3 4x + 7 is not.The coefficients of a polynomial are often taken to be real or complex numbers, but in fact, a polynomial may be defined over any ring.