For a 3×33 \times 33×3 matrix AAA, if det(A−λI)=(1−λ)3\det(A - \lambda I) = (1-\lambda)^3det(A−λI)=(1−λ)3, what is true about AAA?
AAA is the identity matrix.
The only eigenvalue is 111 with algebraic multiplicity 333.
AAA must be diagonalizable.
All entries of AAA are 111.