Cramer's rule/2x2/1/Example

We solve the linear system

${}{\begin{pmatrix}4&3\\-1&5\end{pmatrix}}{\begin{pmatrix}x_{1}\\x_{2}\end{pmatrix}}={\begin{pmatrix}2\\7\end{pmatrix}}\,$

using Cramer's rule. This yields

${}x_{1}={\frac {\det {\begin{pmatrix}2&3\\7&5\end{pmatrix}}}{\det {\begin{pmatrix}4&3\\-1&5\end{pmatrix}}}}=-{\frac {11}{23}}\,$

and

${}x_{2}={\frac {\det {\begin{pmatrix}4&2\\-1&7\end{pmatrix}}}{\det {\begin{pmatrix}4&3\\-1&5\end{pmatrix}}}}={\frac {30}{23}}\,.$