Determinant/Multiplication/5/Exercise

Confirm the Multiplication theorem for determinants for the matrices

$A={\begin{pmatrix}1&4&1\\1&2&0\\0&1&1\end{pmatrix}}\,\,{\text{ and }}\,\,B={\begin{pmatrix}2&0&1\\0&1&0\\1&0&1\end{pmatrix}}.$

Create a solution