CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1)

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Question 17 - CBSE Class 12 Sample Paper for 2022 Boards (MCQ Based - for Term 1) - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Last updated at August 14, 2026 by

Given that A = [𝑎𝑖𝑗] is a square matrix of order 3 × 3 and |A| = −7, then the value of ∑_(i=1) 3 a i2 A i2 "  , where 𝐴 𝑖𝑗 denotes the cofactor of element 𝑎𝑖𝑗  is:

(a) 7  (b) −7  (c) 0  (d) 49

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Question 17 Given that A = [𝑎𝑖𝑗] is a square matrix of order 3 × 3 and |A| = −7, then the value of ∑_(𝑖=1)^3▒"𝑎𝑖2𝐴𝑖2 " , where 𝐴𝑖𝑗 denotes the cofactor of element 𝑎𝑖𝑗 is: (a) 7 (b) −7 (c) 0 (d) 49 Now, = 𝒂_𝟏𝟐 𝑨_𝟏𝟐+𝒂_𝟐𝟐 𝑨_𝟐𝟐+𝒂_𝟐𝟐 𝑨_𝟏𝟐 = Sum of product of elements of Row R2 with its corresponding cofactors = Determinant of A = |A| = 7 So, the correct answer is (B)

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