求助大神，哪里出错了哦，急死我了

MAX=0.9x1+1.4y1+1.9z1+0.45x2+0.95y2+1.45z2-0.05x3+0.45y3+0.95z3;
-0.4x1+0.6y1+0.6z1<=0;
0.2x1+0.2y1-0.8z1>=0;
-0.85x2+0.15y2+0.15z2<=0;
0.6x2+0.6y2-0.4z2>=0;
0.5x3+0.5y3-0.5z3>=0;
x1+x2+x3<=2000;
y1+y2+y3<=2500;
z1+z2+z3<=1200;