在学习一元二次方程根与系数的关系时,我们常会遇到含有一元二次方程ax2+bx+c=0(a≠0)的两根x1,x2的代数式求值问题．常见的题型有两类:关于x1,x2的对称代数式的求值;关于x1,x2的不对称代数式的求值．对于第一类题型,同学们比较熟悉,不再赘述．现重点向同学们介绍解答第二类题的方法． When we study the relationship between the root and the coefficient of a quadratic equation, we often encounter the algebraic expression of two x1, x2 equations containing a quadratic equation ax2+bx+c=0(a≠0). There are two common question types: the evaluation of the symmetric algebraic expression for x1, x2, and the evaluation of the asymmetric algebraic expression for x1, x2. For the first type of questions, the students are more familiar with, not repeat them. The focus is now on introducing students to answering the second question.