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

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

## If A = [8(1 -1 0 2 3 4 0 1 2)] and B = [8(2 2 -4 -4 2 -4 2 -1 5)], then (a) A−1 = B          (b) A−1 = 6B  (c) B−1 = B          (d) B−1 = 1/6 A

### Transcript

Question 25 If A = [■8(1&−1&0@2&3&4@0&1&2)] and B = [■8(2&2&−4@−4&2&−4@2&−1&5)], then (a) A−1 = B (b) A−1 = 6B (c) B−1 = B (d) B−1 = 1/6 A Let’s try multiplying AB AB = [■8(1&−1&0@2&3&4@0&1&2)] [■8(2&2&−4@−4&2&−4@2&−1&5)] = [■8(2+4+0&2−2+0&−4+4+0@4−12+8&4+6−2&−8−12+20@0−4+4&0+2−2&0−4+10)] = [■8(6&0&0@0&6&0@0&0&6)] = 6[■8(1&0&0@0&1&0@0&0&1)] = 6I Thus, AB = 6I 𝟏/𝟔 AB = I So, we can say B−1 = 𝟏/𝟔 A So, the correct answer is (D)

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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 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.