Find $A B$ .
$A = \left[ \begin{array} { c c }
- 2 & 0 \
0 & 4
\end{array} \right] , B = \left[ \begin{array} { c c }
3 & 0 \
0 & - 2
\end{array} \right]$
A) $\left[ \begin{array} { l l }
0 & - 6 \
0 & - 8
\end{array} \right]$
B) $\left[ \begin{array} { c c }
- 2 & 0 \
0 & 4
\end{array} \right]$
C) $\left[ \begin{array} { c c }
- 6 & 0 \
0 & - 8
\end{array} \right]$
D) $\left[ \begin{array} { c c }
0 & - 8 \
- 6 & 0
\end{array} \right]$
E) $\left[ \begin{array} { l l }
- 6 & 0 \
- 8 & 0
\end{array} \right]$

Question

Find $A B$ . 
 $A = \left[ \begin{array} { c c } 
- 2 & 0 \
0 & 4
\end{array} \right] , B = \left[ \begin{array} { c c } 
3 & 0 \
0 & - 2
\end{array} \right]$  
A) $\left[ \begin{array} { l l } 
0 & - 6 \
0 & - 8
\end{array} \right]$
B) $\left[ \begin{array} { c c } 
- 2 & 0 \
0 & 4
\end{array} \right]$
C) $\left[ \begin{array} { c c } 
- 6 & 0 \
0 & - 8
\end{array} \right]$
D) $\left[ \begin{array} { c c } 
0 & - 8 \
- 6 & 0
\end{array} \right]$
E) $\left[ \begin{array} { l l } 
- 6 & 0 \
- 8 & 0
\end{array} \right]$

Quizplus · Accepted Answer

To find $AB$, multiply each element of row $i$ in matrix $A$ by each element of column $j$ in matrix $B$ and sum the products for each $i, j$ position. The result is $\left[ \begin{array} { c c } -2*3+0*0 & -2*0+0*(-2) \ 0*3+4*0 & 0*0+4*(-2) \end{array} \right] = \left[ \begin{array} { c c } -6 & 0 \ 0 & -8 \end{array} \right]$.

Find ABA BAB A=[−2004],B=[300−2]A = \left[ \begin{array} { c c } - 2 & 0 \\0 & 4\end{array} \right] , B = \left[ \begin{array} { c c } 3 & 0 \\0 & - 2\end{array} \right]A=[−20​04​],B=[30​0−2​]

Find $A B$ $A = \left[ \begin{array} { c c } - 2 & 0 \\0 & 4\end{array} \right] , B = \left[ \begin{array} { c c } 3 & 0 \\0 & - 2\end{array} \right]$