For A = [8(3 1 -1 2)], then 14 A −1 is given by

(a) 14 [8(2 -1 1 3)]    (b) [8(4 -2 2 6)]

(c) [8(2 -1 1 -3)]        (d) 2 [8(-3 -1 1 -2)]  

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Question 38 For A = [■8(3&1@−1&2)], then 14 A−1 is given by (a) 14 [■8(2&−1@1&3)] (b) [■8(4&−2@2&6)] (c) [■8(2&−1@1&−3)] (d) 2 [■8(−3&−1@1&−2)] We know that A-1 = 1/(|A|) adj A Now, |𝑨| = |■8(3&1@−1&2)| = 3 × 2 – (−1) × 1 = 6 + 1 = 7 So, the correct answer is (B) A =[■8(3&1@−1&2)] Now, adj A = [■8(3&1@−1&2)] = [■8(𝟐&−𝟏@𝟏&𝟑)] Thus, A-1 = 1/(|A|) adj A = 1/7 [■8(2&−1@1&3)] So, 14A-1 = 14 × 1/7 [■8(2&−1@1&3)] = 2 [■8(2&−1@1&3)] = [■8(2 × 2&2 × −1@2 × 1&2 × 3)] = [■8(𝟒&−𝟐@𝟐&𝟔)] So, the correct answer is (B)

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.