The mathematical formula for finding the root is x =-b √ (b 2-4ac)/(2a). The root formula of quadratic equation with one variable is the basic formula of mathematical algebra, and its purpose is to solve quadratic equation with one variable. Formula method is the solution of quadratic equation with one variable.

According to the relationship between factorization and algebraic expression multiplication, all the coefficients can be directly brought into the formula to find the root, thus avoiding the formula process and finding the root directly. This method of solving a quadratic equation with one variable is called formula method. For multivariate equations, the solution of the equation cannot be said to be the root of the equation.