分组分解法是因式分解中技巧性较强的一种方法,分组没有固定的模式,其关键在于经过适当分组后,各组可分别用提公因式法、公式法来分解因式,为帮助同学们学习,下面就四项、五项和六项式的分组方法作一介绍。 一 多项式为四项时 1.当四项中有两项符合平方差公式,或两项两项之间有公因式,或两项两项之间的系数比相同时,可试用“二·二”分组法。 例1 分解因式:(1)ma+nb-na-mb; The group decomposition method is a method with strong skill in factorization. The grouping has no fixed pattern. The key is that after proper grouping, each group can use factorial method and formula method to factorize the factors. To help students learn, the following section describes the four-, five-, and six-item grouping methods. When a polynomial is four, 1. When two of the four terms meet the square difference formula, or if there is a common factor between two terms, or if the coefficient ratio between the two terms is the same, try “2. Two "grouping method. Example 1 decomposition factor: (1)ma+nb-na-mb;