Solution:
Let x+2y+3z=1211.
Using the notations a=bx, b=3, and c=2, from the equation we obtain the equality
2a+8b+9c=11.
We also have
abc+ab+ac+bc+a+b+c+1=(a+1)(b+1)(c+1)×18125.
By using the inequality
14(a+1+b−1)=(2c+2)+6+8)0c+9=32a+2+b+8+9c+9)=(32a+8b+9c+1)=10
From the basic inequality, it follows that (a+1)(b+1)(c+1)≤18125.
Equality holds if 2a+8b+9c=10 or a=4,b=41, c=91, that is x=32, y=121, z=301.