Find the product AB, if possible.
-$A = \left[ \begin{array} { l l l } - 9 & - 4 & - 4 \ - 4 & - 9 & - 1 \end{array} \right] , B = \left[ \begin{array} { l } - 1 \ - 3 \ - 9 \end{array} \right]$
A)
$\left[ \begin{array} { l } 57 \ 40 \end{array} \right]$
B) $\mathrm { AB }$ is not defined.
C) $\left[ \begin{array} { l l } 57 & 40 \end{array} \right]$
D)

$\left[ \begin{array} { c c c } - 9 & - 4 & - 4 \ - 4 & - 9 & - 1 \ - 1 & - 3 & - 9 \end{array} \right]$

Question

Find the product AB, if possible.
-$A = \left[ \begin{array} { l l l } - 9 & - 4 & - 4 \ - 4 & - 9 & - 1 \end{array} \right] , B = \left[ \begin{array} { l } - 1 \ - 3 \ - 9 \end{array} \right]$
A)
$\left[ \begin{array} { l } 57 \ 40 \end{array} \right]$
B) $\mathrm { AB }$ is not defined.
C) $\left[ \begin{array} { l l } 57 & 40 \end{array} \right]$
D)

$\left[ \begin{array} { c c c } - 9 & - 4 & - 4 \ - 4 & - 9 & - 1 \ - 1 & - 3 & - 9 \end{array} \right]$

Quizplus · Accepted Answer

Matrix multiplication is defined when the number of columns in the first matrix is equal to the number of rows in the second matrix. Here, $A$ is a $2 \times 3$ matrix and $B$ is a $3 \times 1$ matrix, so their product is defined and results in a $2 \times 1$ matrix. Calculating $AB$ gives $\left[ \begin{array} { l } 57 \ 40 \end{array} \right]$.

Find the Product AB, If Possible A) [5740]\left[ \begin{array} { l } 57 \\ 40 \end{array} \right][5740​]

Find the Product AB, If Possible A) $\left[ \begin{array} { l } 57 \\ 40 \end{array} \right]$