乘法公式是初一代数中的重要内容之一 ,应用十分广泛 .现向大家介绍如何应用这些公式的一些常用的技巧和方法 .一、套用分清题目中那些数或式可以看作公式中的字母 ,对号入座 ,套用公式 .例 1　计算 :( 5x2 + 3 y2 ) ( 5x2 -3 y2 ) .分析　将 5x2 与 3 y2 分别看作为平方差公式 The multiplication formula is one of the important contents of the first-generation number, and its application is very extensive. Now we introduce to you how to use these formulas, some commonly used techniques and methods. First, apply the numbers or formulas in the disjunction questions can be regarded as the letters in the formula. , Place a check mark, apply the formula. Example 1 Calculate: (5x2 + 3 y2) ( 5x2 -3 y2 ) . Analysis treats 5x2 and 3 y2 as square difference formulas, respectively