方程,是含有未知数的等式,它不仅是代数的重要内容,也是重要的数学方法,一些表面看来与方程无关的数学问题可以转化成方程问题来解决．这就是方程思想,请看： The equation is an equation containing unknowns. It is not only an important content of algebra, but also an important mathematical method. Some mathematical problems that seemingly have nothing to do with the equation can be converted into equations to solve. This is the idea of ​​equations. See: