平方差公式: (a+b)(a-b) = a2-b2.语言叙述: 两个数的和与这两个数的差的积,等于这两个数的平方的差.在理解平方差公式的基础上,要注意公式的变形应用.解题方法一、找准公式中的a和b例1　计算12a+23b23b-12a .分析　此式为两项之和与两项之差相乘的形式.但这两项在两个括号中 Square difference formula: (a+b)(ab) = a2-b2. Language description: The product of the sum of two numbers and the difference between these two numbers is equal to the difference between the squares of these two numbers. Based on the above, we must pay attention to the application of the formula’s deformation. Problem solving method First, find the a and b in the formula. 1 Calculate 12a+23b23b-12a. Analyze this formula as the sum of two items and the difference between the two items. But these two are in two parentheses