Hi Again Annie;
You ask great questions. Keep these coming!
The lower quantity was made by Jim's team. Therefore, in my opinion, it would be easiest to have his domain represented as x, although other Wyzants may disagree with me.
x=quantity of chips made by Jim's team.
2x-4=quantity of chips made by Nancy's team.
Let's isolate x...
Let's add 4 to both sides...
Let's divide both sides by 3...
Let's check our results...