一、教学背景(一)教材内容分析.学生在第七章第一节已学会利用不等式表示数量之间的不等关系,掌握了不等式的基本性质,能正确运用不等式基本性质将其变形.本节课不仅是前面知识的延续,同时也为后面继续学习利用一元一次不等式解决实际问题以及解一元一次不等式组打下了良好基础.学生在七年级上已经掌握一元一次方程的概念及解法,为本节课的学习做好了铺垫.(二)学生特征分析.七年级的学生虽已经初步掌握一元一次方程的 First, the teaching background (A) textbook content analysis Students in the first quarter of Chapter VII have learned to use inequality that the relationship between the number of inequalities, mastered the basic nature of inequalities, can correctly use the basic properties of inequalities will be deformed. Lesson is not only a continuation of the previous knowledge, but also lay a good foundation for further study to solve the practical problems by using one-element inequality and solving one-element inequality group.Students have mastered the concept and solution of the first order equation (2) analysis of student characteristics. Although the seventh grade students have initially mastered the equation of a unitary equation