An integral equation that contains only one unknown (unary) and the highest order of the unknown is 2 (quadratic) is called unary quadratic equation.

There are four kinds of columns:

① General form

Axe? +bx+c=0(a≠0)

Where ax is a quadratic term and a is the coefficient of the quadratic term; Bx is a basic term; B is the coefficient of the linear term; C is a constant term.

The value of the unknown that makes the left and right sides of the equation equal is the solution of the quadratic equation, and the solution of the quadratic equation is also called the root of the quadratic equation. [2]?

② Variant form

Axe? +bx = 0 (both a and b are real numbers, a ≠ 0);

Axe? +c = 0 (both a and c are real numbers, a ≠ 0);

Axe? =0(a is a real number, a≠0).

③ Matching mode

④ Double root type