What is the meaning of Quadratic_equation?

A polynomial equation of the second degree; an equation that can be rearranged in standard form as ${\displaystyle ax^{2}+bx+c=0}$, where ${\displaystyle x}$ is an unknown value, ${\displaystyle a}$, ${\displaystyle b}$, and ${\displaystyle c}$ are known numbers, and where ${\displaystyle a}$ does not equal zero.

Source: wiktionary.org