1. An equation is an equation containing unknowns.
 2. It is an equation that represents the equal relationship between two mathematical expressions (such as two numbers, functions, quantities and operations). The value of the unknown number that makes the equation true is called "solution" or "root".
 3. The process of solving the equation is called "solving the equation".
 4. The difficulty of reverse thinking can be avoided by solving the equation, and the equation containing the quantity to be solved can be directly listed in the positive direction.
 5. The equation has many forms, such as linear equation of one variable, linear equation of two variables, quadratic equation of one variable, etc. It can also form an equation system to solve multiple unknowns.
 6. In mathematics, an equation is a statement containing an equation of one or more variables.
 7. Solving an equation involves determining which values of variables make the equation hold.
 8. Variables are also called unknowns, and the value of unknowns that meet the equality is called the solution of the equation.