在对比较复杂的多项式进行因式分解时,若把其中某些部分看成一个整体,用新字母代替,能使复杂问题简单化、明朗化,在减少多项式的项数,降低多项式的结构复杂程度等方面有独到的作用,这也就是换元思想在因式分解中的应用． In the factorization of more complex polynomials, if some of these parts are considered as a whole and replaced by new letters, the complex problems can be simplified and clarified. The number of polynomial terms is reduced, and the polynomial structure is reduced. Degrees and other aspects have a unique role, which is also the application of the idea of ​​changing yuan in factorization.