# Variables and Constants

## Variables

### Definition of Variables

The Variables may be defined as the quantity that has no fixed value. The value of the Variables changes and can take various values over time.

### Symbol of Variables

Usually the Variables are denoted by the letters $x, y, z, l, m, n$ etc.

## Constants

### Definition of Constant

A Constant is a quantity that has a fixed value. Any number that can be represented in the number line a constant. The value of a constant never changes over time.

### Example of Constants

$1, 2, 3, -1, -2, -5, 0, 1.5, 6.5$ etc.

## Difference between Constants and Variables

• The main difference between constants and variables is that the constants have a fixed value but the variables do not have any fixed values.
• The face value of a constant remains the same throughout time. However, the value of variables changes over time.
• The constants are represented in numbers but the variables are represented by letters or symbols.

## Solved Examples on Constants and Variables

• An Algebraic Equation is given by, $2x+4=0$. Find the variables and constants.

Solution: In the Algebraic Equation $2x+4=0$, $x$ is the variable and $4$ is the constant. The number $2$ is multiplied with $x$ also a constant and is terms as a coefficient.
The solution of the above algebraic equation is the value of $x$ for which the equation satisfies,
$2x + 4 = 0$
$2x = - 4$
$x = \frac{{ - 4}}{2}$
$x = - 2$
Therefore,$x = - 2$ is the solution of the algebraic equation.

• Find the value of $x$ for the algebraic equation $x + 2 = \frac{5}{2}$?

Solution: Given, $x + 2 = \frac{5}{2}$
$x = \frac{5}{2} - 2$
$x = \frac{{5 - 4}}{2}$
$x = \frac{1}{2}$