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Question
If A = `[(1, 2, 3),(-1, 1, 2),(1, 2, 4)]` then (A2 – 5A)A–1 = ______.
Options
`[(4, 2, 3),(-1, 4, 2),(1, 2, 1)]`
`[(-4, 2, 3),(-1, -4, 2),(1, 2, -1)]`
`[(-4, -1, 1),(2, -4, 2),(3, 2, -1)]`
`[(-1, -2, 1),(4, -2, -3),(1, 4, -2)]`
MCQ
Fill in the Blanks
Solution
If A = `[(1, 2, 3),(-1, 1, 2),(1, 2, 4)]` then (A2 – 5A)A–1 = `underlinebb([(-4, 2, 3),(-1, -4, 2),(1, 2, -1)]`.
Explanation:
(A2 – 5A)A–1 = A2A–1 – 5AA–1
= A.AA–1 – 5I
= A – 5I
= `[(1, 2, 3),(-1, 1, 2),(1, 2, 4)] - [(5, 0, 0),(0, 5, 0),(0, 0, 5)]`
= `[(-4, 2, 3),(-1, -4, 2),(1, 2, -1)]`
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