因式分解的一般步骤可用口诀归纳为:“一提、二数、三检验”.一提是首先观察,若有公因式,就要提出公因式.二数是数一下多项式的项数,若是两项,则用平方差公式来分解;若是三项,则可考虑用完全平方公式来分解;若是四项,则可用分组分解的方法.三检验是分解完毕后,要用整式乘法将自己分解的结果计算出来,与原题目的多项式对照,检验自己的分解是否正确. The general steps of factorization can be summarized as follows: “One mention, two numbers, three tests”. The first observation is that, if there is a common factor, the common factor must be proposed. The second number is the number of polynomials. The number of items, if two items, is decomposed using the squared difference formula; if it is three items, the full square method can be used to decompose; if it is four items, the method of group decomposition can be used. After the three tests are decomposed, they are used. The integral multiplication calculates the results of its own decomposition, and is compared with the polynomial of the original question to test whether its decomposition is correct.