# How do you multiply ((0, 2, 1), (-5, -1, 0)) and ((1, -4, 0), (1, 5, -1))?

They cannot be multiplied as number of rows of first matrix is $2$ and number of columns of the second matrix B is $3$
The general rule is that an $n \times p$ matrix A (with n rows and p columns) can be multiplied by a $p \times m$ matrix B (with p rows and m columns) to form an $n \times m$ matrix AB = C.
In the given cases, as number of rows of first matrix is $2$ and number of columns of the second matrix B is #3, they cannot be multiplied.