First, you would add all the pounds he bought altogether, to know how much he bought, and how many pounds he will divide amongst his friends. That's 3.4 + 2.5 + 4 which equals to 9.9.
So he divides 9.9 pounds of cashews between himself and his two friends, and that makes it dividing 9.9 pounds between two people. That would simply make it : 9.9 ÷ 3, which equals to 3.3
Each friend will get 3.3 pounds of cashews.
        
             
        
        
        
Remember the order of operations and do what is in parenthses first. 
Take 9 to its power first, then add 2. Once you get that, take that answer to the 83721 power. 
I would give you the answer, but my calculator is saying invalid input every time I am trying to use such high exponents. Sorry :( But I hope that this helps