AP EAMCET20224 Jul 2022Morning ShiftMathematicsMatricesActual

If A = 1 7 3 - 2 6 - 6 - 3 2 - 2 6 3 , then

Options

AA - 1 = A
BA - 1 = A T
CA - 1 does not exist
DA - 1 = - A

Correct answer

B. A - 1 = A T

Step-by-step solution

A = 1 7 3 - 2 6 - 6 - 3 2 - 2 6 3 A = 3 7 - 21 49 + 2 7 - 14 49 + 6 7 - 42 7 = - 9 - 4 - 36 49 = - 1 A T = 1 7 3 - 6 - 2 - 2 - 3 6 6 2 3 A - 1 = 1 A A d j A Now A d j A = 1 7 - 21 14 - 42 42 21 - 14 14 - 42 - 21 T = 1 7 - 21 42 14 14 21 - 42 - 42 - 14 - 21 = - 3 6 2 2 3 - 6 - 6 - 2 - 3 Hence, A - 1 = 1 - 1 7 - 3 6 2 2 3 - 6 - 6 - 2 - 3 = 1 7 3 - 6 - 2 - 2 - 3 6 6 2 3

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