The undetermined coefficient method is used to find the analytic expression of quadratic function. According to the known conditions, what kinds of methods are usually used?

The undetermined coefficient method is used to find the analytic expression of quadratic function. According to the known conditions, what kinds of methods are usually used?

General formula: solve the vertex formula of the system of linear equations with three variables, solve the two-point formula of the system of linear equations with one variable, and then solve a