有些方程利用方程的基本性质或公式不易直接求出其解,但经过适当的换元——引入新的辅助未知数,却常常能化难为易,求出其解。本文准备对换元法进行一些探讨与小结。 换元法的一般原理是:如果方程 Some equations use the basic properties or formulas of the equations to find their solutions directly, but after appropriate conversions—the introduction of new auxiliary unknowns—can often make it difficult to find the solution. This article is going to conduct some discussion and summary of the exchange method. The general principle of the substitution method is: If the equation