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MHT CET202015 Oct 2020Evening ShiftMathematicsMatricesActual

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

Options

  1. A( 1 5 ) [ array ll 5 & -5 4 & -5 array ]
  2. B( 1 5 ) [ array cc 5 & -5 -4 & 5 array ]
  3. C( 1 5 ) [ array cc 5 & -5 4 & 5 array ]
  4. D( 1 5 ) [ array cc 5 & -5 -4 & -5 array ]

Correct answer

B. ( 1 5 ) [ array cc 5 & -5 -4 & 5 array ]

Step-by-step solution

A= [ array lll 1 & 2 & 1 2 & 1 & 0 array ] and B= [ array ll 1 & 2 2 & 1 0 & 1 array ] A B array l (A B)⁻¹ = 1 |A B| [ array cc 1+4+0 & 2+2+1 2+2+0 & 4+1+0 array ]= [ array ll 5 & 5 4 & 5 array ] array

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