Find the relative extrema and saddle points of the function. (If an answer does not exist, enter DNE.)

f(x, y) = x^2 + y^2 + 8x 6y + 9.

Relative maximum of f(x, y) =? at (x, y) = ?

Relative minimum of f(x, y) =? at (x, y) = ?

Saddle point of f(x, y) =? at (x, y) = ?