x_1, x_2, x_3, x_4, x_5, x_6, x_7, x_8, x_9, 
-x_3^2
-x_7^2
-x_9^2
-2*x_2*x_3
-2*x_3*x_6
-2*x_4*x_7
-2*x_6*x_9
-2*x_7*x_8
-2*x_8*x_9
-x_1^2+x_4
-2*x_1*x_2+x_5
-2*x_3*x_9-x_6^2
-2*x_1*x_4+2*x_7
-2*x_1*x_7-x_4^2
-2*x_2*x_6-2*x_3*x_5
-2*x_7*x_9-x_8^2
-2*x_5*x_9-2*x_6*x_8
-2*x_1*x_3-x_2^2+x_6
-2*x_4*x_8-2*x_5*x_7-x_8
-2*x_2*x_9-2*x_3*x_8-2*x_5*x_6
-2*x_1*x_5-2*x_2*x_4-x_2+2*x_8
-2*x_4*x_9-2*x_5*x_8-2*x_6*x_7-2*x_9
-2*x_1*x_8-2*x_2*x_7-2*x_4*x_5-x_5
-2*x_1*x_6-2*x_2*x_5-2*x_3*x_4-2*x_3+2*x_9
-2*x_1*x_9-2*x_2*x_8-2*x_3*x_7-2*x_4*x_6-x_5^2-2*x_6
