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消元法解 二元线性方程组

\[ \left\{ \begin{aligned} a_{11}x_1+a_{12}x_2=b_1\\ a_{21}x_1+a_{22}x_2=b_2\\ \end{aligned} \right. \] \[ x_1=\frac{D_1}{D}\\ =\frac{b_1a_{22}-b_2a_{21}}{a_{11}a_{22}-a_{21}a_{12}} , x_2=\frac{D_2}{D} =\frac{a_{11}b_2-a_{21}b_2}{a_{11}a_{22}-a_{21}a_{12}} \]

joy!! haha