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Question: Answered & Verified by Expert
If A is a 3×3 matrix such that |A|=27, AdjA=kAT, then k2-3k+5=
MathematicsMatricesTS EAMCETTS EAMCET 2021 (05 Aug Shift 2)
Options:
  • A 5
  • B 3
  • C 0
  • D 2
Solution:
1526 Upvotes Verified Answer
The correct answer is: 5

Given AdjA=kAT.

AdjA=kAT   ...i

We know that, for a square matrix of order n, AdjA=An-1, kA=knA and AT=A.

Hence, from equation i, we have   

A3-1=k3A

A2=k3A

k3=A=27

k=3.

Hence, k2-3k+5=32-3×3+5=5.

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