解无理方程常将方程两边平方,把方程中的根号“化”去.这种思想方法可以借用到求二次根式的值.有一类二次根式求值问题,直接求,有时非常困难,若把问题转化为解无理方程,则能使问题变得非常简单.举例如下: Solutions to irrational equations often square the equations on both sides and “decrease” the root number in the equation. This idea can be borrowed to find the values ​​of the quadratic roots. There is a class of quadratic root-valued evaluations that are straightforward and sometimes very difficult. If you turn the problem into solving an irrational equation, you can make the problem very simple. Examples are as follows: