Thinking about solving problems For this kind of problems, it is necessary to list inequalities first, and then find out the range of unknown values according to the nature of inequalities. For the first question, we can list the inequality: 8+X.

For the second question, we can list the inequalities:15-x > 6. The solution is: X.

Suggestions on how to learn mathematics well;

1. Establish a study plan: make a reasonable study plan, including daily study time and tasks, and ensure that there is enough time to understand and master mathematics knowledge.

2. Understand the basics: You must understand the basic concepts and formulas of mathematics, which will help you better understand more complicated topics.

3. Problem solving: By doing a lot of exercises, we can consolidate our understanding of mathematical knowledge and improve our ability to solve problems.

4. Help: If you have problems or don't understand, you can ask teachers, classmates or online communities for help.

5. Set the wrong question set: record the wrong questions, analyze the reasons for the mistakes, and avoid repeating the same mistakes.

6. Mastering problem-solving methods: Learning and mastering some problem-solving methods, such as deduction, induction and reduction to absurdity, can help solve various mathematical problems.