If A is a square matrix of order 3 and A' denotes transpose of matrix A, A'A=I, and det A=1, then det(A-I) must be equal to Share with your friends Share 4 Prashant answered this ans=0 -9 View Full Answer Prabhash Ranjan answered this Here the unknown matrix A will be I matrix only....then only it will satisfy the given conditions. Hence answer is 0✌️ 1 Siddharth answered this Prabhash is correct -2 Siddharth answered this Prabhash ranjan is correct 0