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MHT CET202012 Oct 2020Evening ShiftMathematicsMatricesActual

If A= [ array ll 2 & 3 1 & 2 array ], B= [ array ll 1 & 0 3 & 1 array ] , then (A B)⁻¹=

Options

  1. A[ array cc 2 & -3 -7 & 11 array ]
  2. B[ array cc 2 & -3 7 & 11 array ]
  3. C[ array cc 2 & -3 -7 & -11 array ]
  4. D[ array cc -2 & -3 -7 & 11 array ]

Correct answer

A. [ array cc 2 & -3 -7 & 11 array ]

Step-by-step solution

aligned A B &= [ array ll 2 & 3 1 & 2 array ] [ array ll 1 & 0 3 & 1 array ]= [ array cc 11 & 3 7 & 2 array ] |A B|= | array cc 11 & 3 7 & 2 array |=22-21=1 adj (A B) &= [ array cc 2 & -3 -7 & 11 array ] (A B)⁻¹= [ array cc 2 & -3 -7 & 11 array ] aligned

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