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If A, B and (adj(A –1 ) + adj(B –1 )) are non-singular matrices of same order, then the inverse of A(adj(A –1 ) + adj(B –1 )) –1 B, is equal to

1. AB –1 + A –1 B
2. adj(B –1 ) + adj(A –1 )
3. | AB | 1 (adj(B) + adj(A))
4. | B | BA | A | AB 1 1 − − +

Correct answer: | AB | 1 (adj(B) + adj(A))

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