Determinant/Multiplication/3x3/Example 2/Exercise

Confirm the multiplication theorem for determinants for the matrices

$A={\begin{pmatrix}1&4&0\\2&0&5\\0&2&-1\end{pmatrix}}\,\,{\text{ and }}\,\,B={\begin{pmatrix}1&2&7\\0&3&6\\0&-2&-3\end{pmatrix}}.$

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