Hi

You can use matrices.

If X is the vector (x,y) then the equation is

where A is the matrix with -1 and 6 in the first row, and -1 and 4 in the second row

This matrix is diagonalisable since its eigenvalues are 1 and 2

The diagonal matrix is D with 1 ; 0 in the first row and 0 ; 2 in the second row

Then you can find the matrix P such that

If

Then the initial equation becomes which can be easily solved

Then you can find X by