6，AX=ranka- 1

7, 1/ 15

8,

Unknown parameters or statistics

9. Processing method: The common factor k (k = 1, 2, 3...n) is extracted from line k, so it is proposed that the determinant after the common factor is a common determinant in linear algebra: the Vandermonde determinant, and the value of the corresponding coefficient determinant is not 0 directly, so the corresponding equation has only 0 solution.

The solution is K=2.

10，A 1 1 = A 12A- 1 = A6A- 1 = E2A- 1 = A- 1 = 1/det 1

A*={ 1/2

√3/2}

{-√3/2

1/2}