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If A is a square matrix of order 3 and |...

If A is a square matrix of order 3 and `|A|=-2`, then the value of the determinant `|A||adjA|` is

A

`8`

B

`-8`

C

`-1`

D

`-32`

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The correct Answer is:
To solve the problem, we need to find the value of the expression \(|A| \cdot |adj A|\) given that \(|A| = -2\) and \(A\) is a square matrix of order 3. ### Step-by-Step Solution: 1. **Identify the Order of the Matrix**: Since \(A\) is a square matrix of order 3, we have \(n = 3\). 2. **Use the Property of Determinants**: The determinant of the adjoint of a matrix \(A\) is given by the formula: \[ |adj A| = |A|^{n-1} \] where \(n\) is the order of the matrix. For our case: \[ |adj A| = |A|^{3-1} = |A|^2 \] 3. **Substitute the Given Determinant**: We know that \(|A| = -2\). Therefore: \[ |adj A| = (-2)^2 = 4 \] 4. **Calculate the Product**: Now, we need to find \(|A| \cdot |adj A|\): \[ |A| \cdot |adj A| = |A| \cdot |A|^2 = |A|^3 \] Substituting \(|A| = -2\): \[ |A|^3 = (-2)^3 = -8 \] 5. **Final Result**: Thus, the value of \(|A| \cdot |adj A|\) is: \[ \boxed{-8} \]
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