The unary quadratic equation is a simple algebraic equation, that is, the standard form of the unary quadratic equation, and the coefficients of the principal term and the constant term are not zero.

Such as x2-2x+ 1=0. When the coefficient of at least one of the linear term and the constant term is zero, it is called an incomplete quadratic equation.

The quadratic equation of one variable must satisfy three conditions at the same time:

1 is an integral equation, that is, both sides of the equal sign are algebraic expressions, if there is a denominator in the equation; And the unknown is on the denominator, then this equation is a fractional equation, not a quadratic equation. If there is a root sign in the equation and the unknown is within the root sign, then the equation is not a quadratic equation (it is an irrational number equation).

It contains only one unknown number.

The maximum number of unknowns is 2.