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MHT CET202020 Oct 2020Evening ShiftMathematicsMatricesActual

If A= [ array ll 2 & -3 5 & -7 array ] , then 2 A-3 A⁻¹=

Options

  1. A[ array cc 25 & 15 25 & 20 array ]
  2. B[ array cc 25 & 25 -15 & -20 array ]
  3. C[ array cc 25 & -15 25 & -20 array ]
  4. D[ array cc 25 & -25 -15 & -20 array ]

Correct answer

C. [ array cc 25 & -15 25 & -20 array ]

Step-by-step solution

A= [ array ll 2 & -3 5 & -7 array ] |A|=-14+15=1 A⁻¹= [ array cc -7 & 3 -5 & 2 array ] and 2 A= [ array cc 4 & -6 10 & -14 array ] 2 A-3 A⁻¹= [ array cc 4-(-21) & -6-9 10-(-15) & -14-6 array ]= [ array cc 25 & -15 25 & -20 array ]

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