18) Find the function's relative maxima, relative minima, and saddle points, if they exist. (If an answer does not exist, enter DNE.)

18. DETAILS MY NOTES ASK YOUR TEACHER Find the function's relative maxima, relative minima, and saddle points, if they exist. (If an answer does not exist, enter DNE.) z=x2+y28x+6y+5 relative maximum (X, y, z) = ( ) relative minimum (X, y, z) = _ ) saddle point (x, y, z) = ( )