马群同学：来信收到了，内情尽知．你在来信中谈到：你已经掌握了提取公团式法、运用公式法、十字相乘法三种基本的团式分解方法，但是，对分组分解法很生疏．下面我就谈谈这个问题．分组分解法是以前面三种基本方法为基础的一种综合分解方法．在待分解式不很复杂的‘情况下， Ma Qun classmate: The letter was received and the insider knows everything. In your letter, you mentioned that you have mastered the three basic methods of cluster decomposition, such as extracting the corporeal method, using the formula method, and cross-multiplication. However, the group decomposition method is very rusty. I will talk about this issue below. The group decomposition method is a comprehensive decomposition method based on the first three basic methods. In the case that the type of decomposition is not very complicated,