\( y - x y + x - 4 \)

This expression can be simplified and analyzed for better understanding. To make it more manageable, you can factor out \( y \) from the first two terms: \( y(1 - x) + x - 4 \). This rewriting makes it clear how the variables relate, which can be particularly useful in solving equations or optimization problems. In practical situations, expressions like this might represent relationships in fields such as economics, physics, or biology, where variables can represent quantities like profit, distance, or population. Understanding how to manipulate and interpret these expressions can greatly enhance your ability to model real-world scenarios effectively.