Matching method: treat the problem as a quadratic form of a variable and match it into the form of a complete square and an algebraic sum of a constant, so as to discover and study the essence of the problem. This method is often used to solve problems related to quadratic functions and simplified curve equations. Matching method: starting from the overall investigation, through appropriate matching, the problem becomes clear and simple, so as to achieve the purpose of solving the problem relatively easily. Common matching methods are: split term method, dislocation subtraction method, constant substitution method and so on. The key is to practice more. Practice makes perfect.