연립이차방정식

$\displaystyle {\begin{cases} 3 x - 2 y = 7 & \cdots \cdots \text{㉠} \\ \begin{aligned} \\ 6 x ^{2} - xy - 2 y ^{2} = 0 \end{aligned} & \begin{aligned} \\ \cdots \cdots \text{㉡} \end{aligned} \end{cases}}$ ㉡에서 $\left( 2 x + y \right) \left( 3 x - 2 y \right)$$= 0$이고 $3 x - 2 y$$= 7$이므로 $2 x + y$$= 0$, $y$$= \mathit{-} 2 x$ $\cdots \cdots$ ㉢ ㉠, ㉢에서 $x$$= 1$, $y$$= \mathit{-} 2$ $\alpha - \beta$$= 1 - \left( - 2 \right)$$= 3$