c_1, c_2, c_3, c_4, c_5, c_6, c_7, c_8, c_9, x_1, x_2, x_3, x_4, x_5, x_6, x_7, x_8, x_9, 
c_1-x_2
c_2-x_5
c_5-x_7
c_6-x_1
c_7-x_8
c_8-x_9
c_9-x_3
c_4*x_6+2*x_4
-x_6*x_9^2+2*c_3*x_6-2
