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MHT CET202015 Oct 2020Morning ShiftMathematicsMatricesActual

If A= [ array ll 1 & 1 1 & 2 array ], B= [ array ll 4 & 1 3 & 1 array ], then (A+B)⁻¹=

Options

  1. A1 7 [ array ll 3 & 2 4 & 5 array ]
  2. B7 [ array cc 3 & 2 4 & 5 array ]
  3. C1 7 [ array cc 3 & -2 -4 & 5 array ]
  4. D7 [ array cc 3 & -2 -4 & 5 array ]

Correct answer

C. 1 7 [ array cc 3 & -2 -4 & 5 array ]

Step-by-step solution

A+B= [ array ll 1 & 1 1 & 2 array ]+ [ array ll 4 & 1 3 & 1 array ]= [ array ll 5 & 2 4 & 3 array ]|A+B|=15-8=7 and adj (A+B)= [ array cc 3 & -2 -4 & 5 array ] (A+B)⁻¹= 1 7 [ array cc 3 & -2 -4 & 5 array ]

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