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KCET2020MathematicsMatrices

If ( array ll 2 & 1 3 & 2 array ) A= ( array ll 1 & 0 0 & 1 array ) , then the matrix a is

Options

  1. A( array cc 2 & 1 3 & 2 array )
  2. B( array cc 2 & -1 -3 & 2 array )
  3. C( array cc -2 & 1 3 & -2 array )
  4. D( array cc 2 & -1 3 & 2 array )

Correct answer

B. ( array cc 2 & -1 -3 & 2 array )

Step-by-step solution

We have, [ array ll 2 & 1 3 & 2 array ] A= [ array ll 1 & 0 0 & 1 array ] Let B= [ array ll 2 & 1 3 & 2 array ] B A=IA=B⁻¹ IA=B⁻¹ B⁻¹= [ array cc 2 & -1 -3 & 2 array ] Hence, A= [ array cc 2 & -1 -3 & 2 array ]

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