我们学习的二元二次方程组主要是这两种特殊类型：一类是由一个二元二次方程和一个二元一次方程组成的方程组；另一类是由两个二元二次方程组成的方程组（前者简称为“—·一”型，后者简称为。二·工整）．其解法可用Q诀概括如下：“二·一”型常用代入法．和积形式请书达（定 The binary quadratic equations we study are mainly of these two special types: one is a system of equations consisting of a binary quadratic equation and a binary equation, and the other is composed of two binary quadratic equations. The set of equations (the former is referred to as “-·” type, the latter is abbreviated as “two.”) The solution can be summarized as follows Q: “21” commonly used substitution method. The sum of the forms