代入消元法和加减消元法都是二元一次方程组的解法,那么何时使用代入消元法.何时使用加减消元法呢?这是大家学习二元一次方程组解法时常有的困惑.其实,究竟采用哪种方法解方程组应取决于方程组自身的特征.特征不同解法不同,关键是看同学们能否熟练掌握这些特征,并运用到解题当中.特征1:当某一个禾知数的系数是1或-1时,优先考虑代入消元法 Substitution elimination method and addition and subtraction elimination method are binary linear equations of the solution, then when to use substitution elimination method. When to use addition and subtraction elimination method? This is the solution of binary linear equations you often In fact, what kind of method should be used to solve the system of equations should depend on the characteristics of the system itself.Characteristics of different solutions are different, the key is to see whether students are proficient in these features, and use them to solve the problem.Feature 1: When the coefficient of a certain Wo Chi is 1 or -1, priority is given to the elimination method