Find the relative extrema and saddle points of the function. (If an answer does not exist, enter DNE.) f(x, y) = x2 + 6xy + 10y2 − 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) = ( )