1. Let's start by understanding the problem: Exercise 4 likely involves solving or simplifying an algebraic expression or equation. 2. The first step is to identify what the exercise asks: Is it solving for a variable, simplifying an expression, or factoring? 3. Common formulas or rules to remember include the distributive property: $$a(b+c) = ab + ac$$, combining like terms, and solving equations by isolating the variable. 4. If you provide the exact problem statement or expression from Exercise 4, I can guide you step-by-step through the solution. 5. Please share the details of Exercise 4 so I can help you understand it clearly.