If P and Q are non-singular square matrices of the same order, then \((PQ^{-1})^{-1}\) equals
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → \(QP^{-1}\)
By the reversal law for inverses, \((AB)^{-1} = B^{-1}A^{-1}\). With A = P and \(B = Q^{-1}\):
\((PQ^{-1})^{-1} = (Q^{-1})^{-1}P^{-1}\)
\((PQ^{-1})^{-1} = QP^{-1}\)