An equation is an equation that represents the equal relationship between two mathematical expressions (such as two numbers, functions, quantities and operations). It is an equation with unknowns, and there is usually an equal sign "=" between them. Equations do not need reverse thinking, but can be listed directly, including unknowns. It has many forms, such as one-dimensional linear equation, two-dimensional linear equation and so on. It is widely used in the calculation of applied problems in mathematics, physics and other sciences.

A mathematical equation refers to an equation or a set of inequalities containing an unknown number (x). The types of equations are divided according to different numbers of unknowns, different powers of unknowns and different numbers and powers of unknowns.

According to the number of unknowns, it is divided into one-dimensional equation, two-dimensional equation and multivariate equation;

According to the power of the unknown, it can be divided into linear equation, quadratic equation and multivariate equation.

According to the number and power of the unknown, it can be divided into binary linear equation, binary quadratic equation, binary multivariate equation and multivariate multivariate equation. . . .