You are given the quadratic polynomial f(x,y,z) = 2x2 - 2xy- 4xz+y2 +2yz +3z2- 2x + 2z Write f(x,y,z) in form f(x,y,z)= x power x Ax-b power xx where x= (x,y,z) A is a real symmetric matrix, and b is a constant vector. Find the point (x, y, z) where f(x, y, z) is at an extremum. Is this point a minimum, maximum, or saddle point of some kind?