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Let A= [[a,b,c],[p,q,r],[x,y,z]] and sup...

Let `A= [[a,b,c],[p,q,r],[x,y,z]]` and suppose then det (A) = 2, then det (B) equals, where `B = [[4x,2a,-p],[4y, 2b, -q],[4z, 2c, -r]]`

A

-2

B

-8

C

-16

D

8

Text Solution

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The correct Answer is:
To solve the problem, we need to find the determinant of the matrix \( B \) given that the determinant of matrix \( A \) is 2. ### Step-by-step Solution: 1. **Identify the matrices**: We have: \[ A = \begin{bmatrix} a & b & c \\ p & q & r \\ x & y & z \end{bmatrix} \] and \[ B = \begin{bmatrix} 4x & 2a & -p \\ 4y & 2b & -q \\ 4z & 2c & -r \end{bmatrix} \] 2. **Factor out constants from the columns of matrix \( B \)**: - From the first column, we can factor out \( 4 \). - From the second column, we can factor out \( 2 \). - The third column has a factor of \( -1 \) (due to the negative signs). Thus, we can rewrite the determinant of \( B \) as: \[ \text{det}(B) = 4 \cdot 2 \cdot (-1) \cdot \text{det}\left(\begin{bmatrix} x & a & -p \\ y & b & -q \\ z & c & -r \end{bmatrix}\right) \] This simplifies to: \[ \text{det}(B) = -8 \cdot \text{det}\left(\begin{bmatrix} x & a & -p \\ y & b & -q \\ z & c & -r \end{bmatrix}\right) \] 3. **Relate the determinant of the modified matrix to \( A \)**: The matrix we have now can be transformed back to a form similar to \( A \) by rearranging the columns. The determinant of \( A \) is given as \( 2 \). We can express: \[ \text{det}\left(\begin{bmatrix} x & a & -p \\ y & b & -q \\ z & c & -r \end{bmatrix}\right) = -\text{det}(A) \] because we have interchanged columns, which introduces a negative sign. 4. **Substituting the determinant of \( A \)**: Since \( \text{det}(A) = 2 \), we have: \[ \text{det}\left(\begin{bmatrix} x & a & -p \\ y & b & -q \\ z & c & -r \end{bmatrix}\right) = -2 \] 5. **Final calculation**: Now substituting back into the determinant of \( B \): \[ \text{det}(B) = -8 \cdot (-2) = 16 \] ### Conclusion: Thus, the determinant of matrix \( B \) is: \[ \text{det}(B) = 16 \]

To solve the problem, we need to find the determinant of the matrix \( B \) given that the determinant of matrix \( A \) is 2. ### Step-by-step Solution: 1. **Identify the matrices**: We have: \[ A = \begin{bmatrix} ...
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