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MHT CET202123 Sep 2021Evening ShiftMathematicsMatricesActual

If A= [ array ccc 1 & 2 & 3 -1 & 1 & 2 1 & 2 & 4 array ] , then A( adj A)=

Options

  1. A[ array ccc -1 / 3 & 0 & 0 0 & -1 / 3 & 0 0 & & -1 / 3 array ]
  2. B[ array lll 3 & 0 & 0 0 & 3 & 0 0 & 0 & 3 array ]
  3. C[ array ccc 1 & 2 & 3 -1 & 1 & 2 1 & 2 & 4 array ]
  4. D[ array ccc 1 & -1 & 1 2 & 1 & 2 3 & 2 & 4 array ]

Correct answer

B. [ array lll 3 & 0 & 0 0 & 3 & 0 0 & 0 & 3 array ]

Step-by-step solution

aligned & A= [ array ccc 1 & 2 & 3 -1 & 1 & 2 1 & 2 & 4 array ] & |A|=1(4,-4)-2(-4-2)+3(-2-1)=12-9=3 aligned We know that A ( adj A )=| A | I A( adj A)=3 [ array lll 1 & 0 & 0 0 & 1 & 0 0 & 0 & 1 array ]= [ array lll 3 & 0 & 0 0 & 3 & 0 0 & 0 & 3 array ]

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