The matrix $A$ is the coefficient matrix, $X$ is the variable matrix, and $B$ is the constant matrix. So, we have:
$$A=\left[\begin{array}{ll}-1 & 1 \\ -2 & 1\end{array}\right], X=\left[\begin{array}{l}x_{1} \\ x_{2}\end{array}\right], B=\left[\begin{array}{l}4 \\
Show more…