Constants
A symbol having a fixed numerical value is called a constant
Example:- 6 , 7 , 8/9 ,√5 , π are all constants.
Variables
A symbol which may be assigned different numerical values is known as a variable.
Examples:- we know that the area of a circle is given by the formula A=πr^2,where r is the radius of the circle.
here π is constant,while A and r are variables.
Algebraic Expressions
A combination of constants and variables,connected by some or all of the all operations +, - , × , ፥ ,is known as an algebraic expression.
Term of an algebriac expression separated by + or - operations are called the terms of the expression.
Examples:- (i) 3x^2 - 9x+6 is an algebraic expression containing three terms,namely 3x^2 , -9x and 4.
(ii) 2x^3+ √5x^2-(3/7)x+7 is an algebraic containing four terms,namely 2x^3,√5x^2, -(3/7)x , 7.
(iii) k^7 - 128 is an algebraic expression containing two terms,namely k^7 and -128.
