Variable: Examples of Variables, Variable in Statistics and Types of Variables

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In Maths, a variable is an alphabet or term that represents an unknown number. The variables are specially used in the case of algebraic expression or algebra. The variable is a quantity that can be changed, or which is not fixed according to the mathematical operation performed. We express an unknown number using the term ‘x’ and ‘y’ or any other alphabet

What is a Variable?

Variable Definition: Variable is an alphabetic character speaking to a number, called the estimation of the variable, which is either discretionary or not completely indicated or obscure.

Making arithmetical calculations with variables as though they were express numbers permits one to take care of scope of issues in a solitary calculation. An ordinary illustration is a quadratic recipe, which allows one to explain each quadratic condition by just substituting the numeric estimations of the coefficients of the offered condition to the variables that speak to them.

The idea of a variable is likewise major in math. Regularly, a capacity includes two variables, y and x, speaking to individually the quality and the contention of the capacity. The expression “variable” originates from the way that, when the contention (additionally called the “variable of the capacity”) shifts, then the quality changes accordingly.

Examples of Variables

In the above examples, x and y are called variables.


The constant in math are the values which cannot be changed, or which are fixed. It is a contradiction to the variable. In algebraic expressions, the constant are terms which define themselves.

For example, if is an equation, then,

is the variable, which can have different values and 9 is the coefficient of .

But numbers 2 and 15 are the constant here.

Variable in Statistics

Variables are used in terms of real-life scenarios. It is also said to be an attribute here. They are used to represent people, place, thing, etc. For example, hair-colour could vary from person to person like for some it is blond, for some, it is black, etc.

Types of Variables

The variables can be classified into two categories, namely

  • Dependent Variable

  • Independent Variable

Dependent Variables

The dependent variable is characterized as the variable whose quality depends on the estimation of another variable in its condition. That is, the estimation of the word variable is dependably said to be reliant on the free variable of math condition.

For instance, consider the condition . In this condition, the estimation of the variable changes as per the adjustments in the estimation of . In this manner, the variable is said to be a reliant variable. A portion of the cases that include subordinate variables is talked about in point of interest as beneath with their answers.

Independent Variables

In an algebraic equation, independent variable describes a variable whose values are independent of changes. If x and y are two variables in an algebraic equation and every value of x is linked with any other value of y, then ‘y’ value is said to be a function of x value known as an independent variable, and ‘y’ value is known as a dependent variable.

Example: In the expression is an independent variable and is a dependent variable.

Q. 1 Solve the below example.



Here one variable ,

We take the x variable on the one side and numbers one side.

Sum of x and numbers,

To find the value of x, 4 take the right hand side.

Therefore, value of x is

(b) If the value of , then find the value of y.


Here given, and

Put the value of x in given expression.

(c) Solve the