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Question
If A and B are square matrices of the same order 3, such that ∣A∣ = 2 and AB = 2I, write the value of ∣B∣.
Solution
We have, AB = 2I
`|"AB"| = |2"I"|`
⇒ `|"A"| |"B"| = 8`
⇒ `2 |"B"| = 8 ...("Given" |"A"| = 2)`
⇒ `|"B"| = 4`
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