matA : 
The matrix is not symmetry.

matB : 
 K = 1 	 Determinant = 3
 K = 2	 Determinant = 15
 K = 3	 Determinant = 13
The matrix is symmetry and regular.

matC : 
 K = 1 	 Determinant = 5
 K = 2	 Determinant = 1
 K = 3	 Determinant = 2
 K = 4	 Determinant = 55
The matrix is regular.