To solve the equation , you’ll want to isolate by dividing both sides by 18. So, , which simplifies to . Easy peasy!

Now, let’s think about its real-world application: Imagine you’re mixing a drink where for every 18 ounces of liquid, you know the total is -9 ounces for a particular ingredient—this equation can help you see how much of that ingredient to use! Understanding how to manipulate equations can help you in everything from budgeting to cooking.