In a 3×3 matrix 𝐴, the sum of the elements in each row is 2020. Show that 2020 is an eigenvalue of 𝐴.

Answer 1

^{As a hint, From A-λI = 0 then A= λI. λI would have only the eigenvaues on the diagonal. zeroes elsewhere. Each row would add up to 2020 since that's all there is in a row.}