Hi there! To help you with this, all you have to do is add or subtract the number on the left, depending what the number is to get the variable by itself. If the number is positive with a plus sign, you add. If the number is negative with a minus symbol, you add. With that being said, here are the answers to help you out.
1. B: 8
2. A: 8
3. A: 25
4. C: -1