Let AAA have eigenvalues λ1,λ2,λ3\lambda_1, \lambda_2, \lambda_3λ1,λ2,λ3. What are the eigenvalues of A+3IA + 3IA+3I?
λ1+3,λ2+3,λ3+3\lambda_1+3, \lambda_2+3, \lambda_3+3λ1+3,λ2+3,λ3+3
3λ1,3λ2,3λ33\lambda_1, 3\lambda_2, 3\lambda_33λ1,3λ2,3λ3
λ13,λ23,λ33\lambda_1^3, \lambda_2^3, \lambda_3^3λ13,λ23,λ33
1/λ1,1/λ2,1/λ31/\lambda_1, 1/\lambda_2, 1/\lambda_31/λ1,1/λ2,1/λ3