The teacher will be very surprised to see your correct solution 😉
2 2 2 3 - 25*x2 - 11*x4 - 4*x1 - 2*x3 - 10*x2*x3 - 6*x1*x4 + 2*x3*x4 + 4*x1*x3 + 16*x2*x4 + 20*x1*x2 = 0
-4*x1^2 + 20*x1*x2 + 4*x1*x3 - 6*x1*x4 - 25*x2^2 - 10*x2*x3 + 16*x2*x4 - 2*x3^3 + 2*x3*x4 - 11*x4^2 = 0