Find the best solutions to your problems with the help of IDNLearn.com's expert users. Our experts provide timely, comprehensive responses to ensure you have the information you need.

Given the matrices [tex]\( A \)[/tex] and [tex]\( B \)[/tex], compute [tex]\( 2A - 3B \)[/tex].

[tex]\[
A = \left[\begin{array}{rrr}
-1 & 0 & 2 \\
4 & 1 & -1 \\
2 & 0 & 1
\end{array}\right]
\quad
B = \left[\begin{array}{rrr}
2 & 1 & 0 \\
-1 & 0 & 2 \\
4 & -3 & 1
\end{array}\right]
\][/tex]

Enter the element in row 3, column 1 of [tex]\( 2A - 3B \)[/tex].


Sagot :

To solve the problem, we'll follow the specified steps carefully and calculate the required quantities step-by-step.

1. Matrix A and Matrix B:
[tex]\[ A = \begin{pmatrix} -1 & 0 & 2 \\ 4 & 1 & -1 \\ 2 & 0 & 1 \end{pmatrix} \][/tex]
[tex]\[ B = \begin{pmatrix} 2 & 1 & 0 \\ -1 & 0 & 2 \\ 4 & -3 & 1 \end{pmatrix} \][/tex]

2. Compute [tex]\(2A\)[/tex]:
We multiply each element of [tex]\(A\)[/tex] by 2.
[tex]\[ 2A = 2 \cdot \begin{pmatrix} -1 & 0 & 2 \\ 4 & 1 & -1 \\ 2 & 0 & 1 \end{pmatrix} = \begin{pmatrix} -2 & 0 & 4 \\ 8 & 2 & -2 \\ 4 & 0 & 2 \end{pmatrix} \][/tex]

3. Compute [tex]\(3B\)[/tex]:
We multiply each element of [tex]\(B\)[/tex] by 3.
[tex]\[ 3B = 3 \cdot \begin{pmatrix} 2 & 1 & 0 \\ -1 & 0 & 2 \\ 4 & -3 & 1 \end{pmatrix} = \begin{pmatrix} 6 & 3 & 0 \\ -3 & 0 & 6 \\ 12 & -9 & 3 \end{pmatrix} \][/tex]

4. Compute [tex]\(2A - 3B\)[/tex]:
We subtract the matrix [tex]\(3B\)[/tex] from [tex]\(2A\)[/tex], element-wise.
[tex]\[ 2A - 3B = \begin{pmatrix} -2 & 0 & 4 \\ 8 & 2 & -2 \\ 4 & 0 & 2 \end{pmatrix} - \begin{pmatrix} 6 & 3 & 0 \\ -3 & 0 & 6 \\ 12 & -9 & 3 \end{pmatrix} = \begin{pmatrix} -2 - 6 & 0 - 3 & 4 - 0 \\ 8 + 3 & 2 - 0 & -2 - 6 \\ 4 - 12 & 0 + 9 & 2 - 3 \end{pmatrix} \][/tex]
Simplifying further:
[tex]\[ 2A - 3B = \begin{pmatrix} -8 & -3 & 4 \\ 11 & 2 & -8 \\ -8 & 9 & -1 \end{pmatrix} \][/tex]

5. Element in row 3, column 1:
In matrix notation, row 3, column 1 corresponds to the element at (3,1).

From our calculated matrix [tex]\(2A - 3B\)[/tex]:
[tex]\[ \begin{pmatrix} -8 & -3 & 4 \\ 11 & 2 & -8 \\ -8 & 9 & -1 \end{pmatrix}_{(3,1)} = -8 \][/tex]

Thus, the element in row 3, column 1 of [tex]\(2A - 3B\)[/tex] is [tex]\(-8\)[/tex].