x_1, x_2, x_3, x_4, 
-5*x_1^2+x_3
-9*x_1^5+12960*x_1^3-4100*x_1^2-4608000*x_1+320*x_4+2560000
9*x_1^6-12960*x_1^4+10500*x_1^3+4608000*x_1^2-7680000*x_1+3200000
18*x_1^5+15*x_1^4-25920*x_1^3-600*x_1^2+9225500*x_1+2000*x_2-7680000
