1. The problem statement, all variables and given/known data f = x^2 + 4xy + y^2 + 6x + 8 Find minimum, maximum, or saddle point 2. Relevant equations A = [f_xx, f_xy; f_yx, f_yy] 3. The attempt at a solution Found the determinant to be zero ( i got [2 ,4; 4, 2] ) so i cant use the eigenvalues to determine the extrema. now what do i do? If I am to use lagrange multipliers, how do i do that without a constraint?