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Class 12
Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Given that A is a square matrix of order 3 and |A| = βˆ’4, then adj A| is equal to:

(a) βˆ’4Β  Β  Β (b) 4
(c) βˆ’16Β  Β (d) 16

This question is inspired from Question 5 (Choice 2) - CBSE Class 12 Sample Paper for 2021 Boards

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Question 6 Given that A is a square matrix of order 3 and |A| = βˆ’4, then adj A| is equal to: (a) βˆ’4 (b) 4 (c) βˆ’16 (d) 16 We know that |𝒂𝒅𝒋 𝑨| = |𝑨|^(π’βˆ’πŸ) where n is the order of determinant Given Order = n = 3 So, |π‘Žπ‘‘π‘— 𝐴| = |A|^(3βˆ’1) |π‘Žπ‘‘π‘— 𝐴| = |A|^2 |π‘Žπ‘‘π‘— 𝐴| = (βˆ’4)2 |𝒂𝒅𝒋 𝑨| = 16 So, the correct answer is (d)

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