Essay

$\text { Let } \boldsymbol { A } = \left[ \begin{array} { l l l } 1 & 2 & 3 \\0 & 1 & 4\end{array} \right] \text { and } \boldsymbol { B } = \left[ \begin{array} { l l } 1 & 2 \\0 & 1 \\2 & 3\end{array} \right] \text {. Find } \boldsymbol { A } \boldsymbol { B } \text { and } \boldsymbol { B } \boldsymbol { A } \text {. Are they equal? }$