foass77W

2021-01-10

If possible , find $2A-4B$
$A=\left[\begin{array}{ccc}-3& 5& -6\\ 3& -5& -1\end{array}\right],B=\left[\begin{array}{ccc}-6& 8& -3\\ 3& 6& -2\end{array}\right]$
a. $\left[\begin{array}{ccc}-30& 42& -24\\ 18& 14& -10\end{array}\right]$
b. not possible
c. $\left[\begin{array}{ccc}1& 0& 0\\ 0& 1& 0\end{array}\right]$
d. $\left[\begin{array}{ccc}-9& 13& -9\\ 6& 1& -3\end{array}\right]$
c. $\left[\begin{array}{ccc}18& -22& 0\\ -6& -34& 6\end{array}\right]$

yunitsiL

Step 1
Considering the matrices provided
Since, the order of the matrix A is $2×3$(2 rows and 3 columns) and also order of the matrix B is $2×3$
The matrices A and B are in the same order in this case.
So, subtraction of matrix $2A-4B$ is possible.
Step 2
Now, find $2A-4B$.
$A=\left[\begin{array}{ccc}-3& 5& -6\\ 3& -5& -1\end{array}\right],B=\left[\begin{array}{ccc}-6& 8& -3\\ 3& 6& -2\end{array}\right]$
Now , $2A-4B=2\left[\begin{array}{ccc}-3& 5& -6\\ 3& -5& -1\end{array}\right]-4\left[\begin{array}{ccc}-6& 8& -3\\ 3& 6& -2\end{array}\right]$
Multiply 2 and 4 every element of matrix A and B respectively.
$=\left[\begin{array}{ccc}-6& 10& -12\\ 6& -10& -2\end{array}\right]-\left[\begin{array}{ccc}-24& 32& -12\\ 12& 24& -8\end{array}\right]$
$=\left[\begin{array}{ccc}-6-\left(-24\right)& 10-32& -12-\left(-12\right)\\ 6-12& -10-24& -2-\left(-8\right)\end{array}\right]$
$=\left[\begin{array}{ccc}-6+24& -22& -12+12\\ -6& -34& -2+8\end{array}\right]$
$=\left[\begin{array}{ccc}18& -22& 0\\ -6& -34& -6\end{array}\right]$

Jeffrey Jordon

Answer is given below (on video)

Jeffrey Jordon