An equation in which one or more of the terms is squared but raised to no higher power, having the general form ax + bx + c = 0, where a, b, and c are constants. an equation such ax²+by+c = z, which includes numbers or quantities multiplied by themselves (quadratic from quadrate (14-21 centuries), from quadratus, past participle of quadrare ). Algebraic equation of particular importance in optimization. A more descriptive name is second-degree polynomial equation. Its standard form is ax^2 + bx + c = 0, and its solution is given by the quadratic formula