If $A$ is a square matrix of order 3 and

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Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Matrices

Question:

If $A$ is a square matrix of order 3 and $|A| = -5$, then $|3A|$ is equal to

Options:

-135

-15

135

Correct Answer:

-135

Explanation:

The correct answer is Option (1) → -135

For a square matrix of order $n$, the determinant satisfies:

$|kA| = k^n \cdot |A|$

Here, $n = 3$, $k = 3$, and $|A| = -5$.

$|3A| = 3^3 \cdot (-5) = 27 \cdot (-5) = -135$