解一元二次方程是学生必须熟练掌握的基本技能 .教材中介绍了四种基本方法 :直接开平方法、配方法、求根公式法、因式分解法 .有些方程在具体求解时 ,不能直接套用这四种基本方法 ,这时就需要认真分析方程的特点 ,选好突破口 ,施以适当的技巧 .现举例说明 .　　一、巧提公因式 The solution of a quadratic equation is a basic skill that students must master. There are four basic methods introduced in the textbook: direct opening method, matching method, root formula method, factorization method. Some equations can not be directly applied in the concrete solution. These four basic methods, then need to carefully analyze the characteristics of the equation, select a breakthrough, and apply appropriate skills. Now illustrate. A, clever public reason