Answer:
When the number of rows or number of columns in the given matrix does not match the number of entries in the vector x.
When the number of columns in A [tex]\neq[/tex] the number of rows in B.
The matrix-vector is not defined.
Step-by-step explanation:
For example:-
Step 1:
Let's assume
[tex]A=\left ( \begin{matrix}-6 & 9\\ 2& 7\\ 1 & 0\end{matrix} \right )[/tex]3x2 & [tex]B=\left ( \begin{matrix}1\\ -6\\ 7\end{matrix} \right )[/tex]3x1
Since matrix multiplication of matric A and matrix B is only possible,
When the number of columns in A = Number of rows in B.
Step 2:
Let's A as m x n; Here m = rows and n=columns
B as p x q; Here p = rows and q=columns.
When n [tex]\neq[/tex] p, the matrix-vector is not defined.
That is matrix multiplication Ax is not possible.
Hence the matrix is not defined.
