Which pair of matrices are inverses of each another?

If we put symbols for the numbers in the first matrix 
 
to find the inverse of the first matrix
first we need to find the determinant (D)
D = ad - bc
a = 2, b = 3 , c = 6 and d = 8
D = 2x8 - 3x6
    = 16 - 18
    = -2
then to find the inverse we have to exchange a and d and also multiply b and c by -1
and divide all the terms in the matrix by determinant 
inverse matrix is then 
 
simplified matrix, the answer of inverse matrix is