The first method of solving problems: matching method.
Matching method is a technique of directionally deforming a mathematical formula (matching it into a "complete square"), so as to find the connection between the known and the unknown through the formula, thus simplifying the complex. When making a formula, we need to properly predict and reasonably use the skills of "splitting items" and "adding items", "matching" and "getting together" to complete the formula. It is sometimes called the "combination method".
The most common formula is to carry out identical deformation to make the mathematical formula completely square. It is mainly suitable for the discussion and solution of known or unknown quadratic equations, quadratic inequalities, quadratic functions and quadratic algebra, or the translation transformation of quadratic curves with missing items.