2元連立1次方程式

$$\left[ \begin{array}{cc} a_{11}& a_{12}\ a_{21}& a_{22} \end{arr... ... \end{array} \right] = \left[ \begin{array}{c} b_1\ b_2\ \end{array} \right]$$ (16)

の解

$$\left[ \begin{array}{c} x\ y\ \end{array} \right] = \frac{1}{a_... ...11} \end{array} \right] \left[ \begin{array}{c} b_1\ b_2\ \end{array} \right]$$ (17)

$$x=\frac{a_{22}b_1+a_{12}b_2}{a_{11}a_{22}-a_{12}a_{21}} ,\qquad y=\frac{-a_{21}b_1+a_{11}b_2}{a_{11}a_{22}-a_{12}a_{21}}$$