在解题中,经常会遇到一些用常规方法求解非常麻烦或几乎无法下手的题目．但我们如果能够灵活地运用等式变形,则可以独辟蹊径,使难题迎刃而解,达到事半功倍的效果．如何利用等式变形?笔者根据多年的教学经验认为可以有以下三种：①直接变形法；②增减变形法；③假设变形法．(?) In solving a problem, you often encounter some problems that are very difficult or almost impossible to solve with conventional methods. However, if we can flexibly use the isomorphic deformation, we can use our own way to solve the problem and achieve a multiplier effect. How to use the equation deformation? According to many years of teaching experience, the author believes that there are three ways: 1 direct deformation method; 2 increase and decrease deformation method; 3 hypothetical deformation method. (?)