因式分解是学习分式运算的基础，解方程或方程组时常用到它．它的重要性是众所周知的．为使同学们牢固掌握因式分解的方法，按教材的要求，在提取公因式后，根据多项式项数的不同（有时把一个整体看作一项），给同学们介绍一些常用的方法，同学们掌握这些方法后，解题时能“对? Factorization is the basis for learning fractional operations. It is often used to solve equations or equations. Its importance is well known. In order to enable the students to firmly master the method of factorization, according to the requirements of the teaching materials, after extracting the common factors, according to the different number of polynomial terms (sometimes considering a whole as one item), students are introduced to some commonly used methods. After the students have mastered these methods, they can solve the problem "right?