Definition of an equation

An equation is an statement in which two expressions are related by an equals sign. At least one of the expressions must contain variables.

Example of an equation.

The equation

3x - 1 = 20

The equation has left-hand side

3x - 1

and right-hand side

20

Terms of the equation are

3x, -1, 20.

The variable (unknown) is x.

The 3 in 3x is called a coefficient or a parameter.

Solving the equation.

Solving the equation means to find the values of the variable x making the equality true.

This equation has the unique solution

x = 7