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If A= [ array ccc 2 & & 0 -2 & & 0 -1 & 1 & 1 array ] , then what is A( adj A) equal to? where I is the identify matrix.

Options

  1. ANullmatrix
  2. B-I
  3. CI
  4. D2I

Correct answer

D. 2I

Step-by-step solution

|A|= | array ccc 2 & & 0 -2 & & 0 -1 & 1 & 1 array |=2 We know that A( adj A)=|A| I=2 I

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