Let A be a 4 × 4 matrix with eigenvalues -5, -2, 1, 4. Which of the following is an
eigenvalue of
A I
I A
where I is the 4 × 4 identity matrix?
(A) -5 (B) -7 (C) 2 (D) 1
I am not able to find out relation between eigenvalues of matrix A and of the given block matrix.