Identify each matrix A such that A^2 has identical diagonal elements?

The correct matrices are:

Matrix:

7 1 5

1 5 7

5 7 1

all diagonal elements of A^2 are: 7^2 + 1^2 + 5^2

Matrix:

9   18  27

27 -9  18

18  27 9

all diagonal elements of A^2 are: 9^2 + 27*18 + 18*27   or (-9)^2

Matrix:

8 1 6

6 8 1

1 6 8

all diagonal elements of A^2 are: 8^2 + 6*1 + 1*6

1.3 million hoops i believe