师：我们已经知道，解二元一次方程组的基本思想是消元，即将二元化为一元，但消元的方法是多种多样的．下面请大家把课本翻到第22页，我们以第3（2）题为例，来看看可用哪些常用方法消元．张华：首先，这道题可用代入法消元．原方程组可化为由①可得y＝3x－8．把③代入②，得3 Teacher: We already know that the basic idea of ​​solving the binary equations is to eliminate the yuan, that is, to convert it into a dollar, but the method of elimination is various. Now, please turn the textbook to page 22. Let’s take the third (2) example as an example to see which common methods can be used to eliminate the yuan. Zhang Hua: First of all, this question can be substituted into the elimination method. The original equations can be changed from 1 to y=3x-8. Substitute 3 into 2 to get 3