For the partial differential equation $8\frac{\partial^2 u}{\partial x^2}+4\frac{\partial^2 u}{\partial x\partial y} - 1\frac{\partial^2 u}{\partial y^2}+2\frac{\partial u}{\partial x}+5\frac{\partial u}{\partial y}+7 u=0$ the discriminant is
The PDE is (check all that apply)

Your overall score for this problem is