MCQ
If $AB = A$ and $BA = B$, then
  • A
    $A^2B = A^2$
  • B
    $B^2A = B^2$
  • C
    $ABA = A$
  • All of the above

Answer

Correct option: D.
All of the above
d
We have $A^2B = A(AB) = AA = A^2$, $B^2A = B(BA) = BB = B^2$,
$ ABA = A(BA) = AB = A$, and $BAB = B(AB) = BA = B$

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