The main content of this chapter focuses on exploring and applying methods for solving problems of the form:

• Equations reducible to first-degree equations in one variable: These are equations that may seem complex at first but can be transformed into the basic form ax + b = 0 to determine the value of the variable x.
• First-degree equations in two variables and systems of two first-degree equations in two variables: These problems involve two variables (x, y) and are represented by two equations. Solving the system allows us to find both values of x and y at the same time, satisfying both equations simultaneously.

Applications and significance when learning

Mastering knowledge of first-degree equations and systems of first-degree equations is extremely important and meaningful, not only in learning but also in real-life situations:

• Solving real-life problems: Most issues, from simple to complex in life, such as calculating costs, allocating resources, or determining area and volume, can be modeled and solved using equations. For example, calculating the area of a piece of land is an application of equations.
• Developing logical thinking and problem-solving skills: Learning how to set up and solve equations helps you practice analytical skills, logical thinking, and approach a problem systematically.
• A foundation for higher-level mathematics knowledge: Knowledge of first-degree equations is a solid foundation for learning more complex types of equations and inequalities later on, such as quadratic equations, exponential equations, logarithmic equations, and systems with more variables.

In summary, studying this chapter provides you with a powerful tool to solve problems, not only in Mathematics but also in many other fields of science and everyday life.