例谈求代数式的值陶永文一、注意定义、公式、法则和定理的逆向运用，能使运算简便。在学生能够熟练地正确运用定义、公式、法则和定理之后，教师还要培养学生逆向运用定义、公式、法则和定理的能力。在“活”字上下功夫，使计算简便：例１．已知ｘ２＋ｘ＋１＝０，求ｘ１... Examples of the value of algebraic expressions Tao Yongwen First, pay attention to the inverse use of definitions, formulas, rules and theorems, which can make the operation simple. After students can skillfully use definitions, formulas, rules, and theorems, teachers must also develop students’ abilities to use definitions, formulae, rules, and theorems in reverse. Work hard on the word “live” to make calculations simple: Example 1. Known x2+x+1=0, find x1...