因式有理化是恒等变型中的一种重要思想.初中阶段较常见的是二次根式的有理化,通过分子、分母同乘以分子(母)的有理化因式,化去分子(母)的根号,称为分子(母)有理化,本文着重探讨利用因式有理化来解一类数学竞赛题. The rationalization of the formula is an important idea in the isomorphic variant. The more common in the junior middle school is the rationalization of the quadratic roots. By means of the rationalization of the numerator (mother) by numerator and denominator, ) Root number, known as the molecular (mother) rationalization, this article focuses on the use of rational rationalization to solve a class of math competitions.