x_1, x_2, x_3, x_4, x_5, x_6, x_7, x_8, 
-2*x_2^2+9*x_3
6*x_5+x_2
6*x_6+x_2
x_2^2*x_4+12*x_8
72*x_1*x_7^2-x_2^2*x_4
