平方差公式是乘法公式中最基本的公式之一.公式中的a,b可以表示一个数,一个单项式或一个多项式,当表示分数或多项式或分式时,应加括号,可形象表示为(□+△)(□-△)=□2-△2.使用公式时,应先观察所给式子的结构特征是否符合公式的条件.如符合,则直接套用公式进行运算;如不符合,应先变形为公式的形式与结构,再加以利用.通常,我们利用这一公式来计算时,往往是从原 The square difference formula is one of the most basic formulas in the multiplication formula, where a and b can denote a number, a monomial or a polynomial. When expressing a fraction or a polynomial or a fraction, □ + △) (□ - △) = □ 2 - △ 2. When using the formula, you should observe whether the structural characteristics of the given formula meets the conditions of the formula, if so, apply the formula directly; if not, Should be deformed into the form and structure of the formula, and then to use.Usually, we use this formula to calculate, often from the original