1. The general idea is to decompose the partially decomposed polynomial as a whole.

2. Analogical thinking:

Specific performance: the comparison between factorization and algebraic expression multiplication.

B. Comparison of distribution laws between factorization and multiplication

C. comparison of factorization and multiplication formulas

3. Transformation ideas: Some polynomials that cannot be directly decomposed can be decomposed if they are transformed, such as adding terms and splitting terms.

4. the idea of substitution: that is, replacing some terms of polynomial with other letters. By substitution, we can transform a complex polynomial into a simple polynomial, an unfamiliar form into a familiar form, and then decompose the factors.