Factorization is an important identity deformation of algebra. Although "Mathematics Curriculum Standard" reduces the requirements of special skills of factorization, and reduces the four commonly used methods of factorization to two, and the application of formula method to two, it does not deny the educational value of factorization and its important role in algebraic operation. The textbook in this chapter is put forward on the basis of students' learning algebraic expression operation. In fact, it is the reverse application of algebraic multiplication and is closely related to algebraic multiplication. The deformation of factorization not only embodies the idea of "simplification", but also is the basis for solving the subsequent identical deformation, such as fractional simplification and solving equations, which provides an effective way for mathematical communication. Factorization plays a connecting role in the whole textbook. The educational value of this chapter is also reflected in making students accept the view of unity of opposites and cultivating students' ability to observe, analyze, predict and solve problems correctly.

Analysis of learning situation

By exploring the square difference formula and decomposing factors by using the square difference formula, students can express their views, benefit from communication, gain successful experience, exercise their will to overcome difficulties and establish self-confidence.

Teaching objectives

1. Experience the relationship between algebraic expression multiplication and factorization in the process of factorization.

2. Through the reverse deformation of formula a -b =(a+b)(a-b), the abilities of observation, induction and analogy are further developed. To cultivate the ability of orderly thinking and language expression.

3. Common factor method and formula method can be used for comprehensive application.

4. Through activity 4, transform the high even exponential power into quadratic exponential power, and cultivate students' transformational thinking.

Teaching emphases and difficulties

Key points: Flexible use of variance formula to decompose factors.

Difficulties: the derivation and application of square difference formula, and the comprehensive application of two factorization methods (common factor method and square variance formula).