# Algebraic Expressions

**Constants**

A symbol having a fixed numerical value is called a constant.

**Example :** 3 - 5, , p etc.

**Variable**

A symbol or alphabet which takes on various numerical values is known as variable.

**Example :** Circumference of a circle C = 2p *r *

Where* r *- radius of the circle2,

*p*- constants

C,* r *- variables

**Algebraic Expressions**

A symbol or alphabet which takes on various numerical values is known as variable.

**Terms :** The several parts of the expression separated by + or - sign are called the terms of the expression.

**Example :** is an expression containing four terms. They are 2, 5*x*, -8*x*^{2}*y *and

*.*

Mr. Sharma having 2 pencils, 5 pens then form a algebraic expression to express this information.

Let us denote number of pencils by the variable* x *and number of pens by the variable *y.* Then the algebraic expression is 2*x* + 5*y*.

**Polynomials**

An algebraic expression in which the variables involved have only non-negative integral powers is called a polynomial.

**Example :**

(i) * * is a polynomial in one variable* *x.

(ii) is a polynomial in two variables* x* & y.

(iii) * * is not a polynomial. is not a non-negative integer.

(iv) is not a polynomial. - 8 is not a non-negative integer.