Page 1 - ln

SAI International School

CLASS – VIII,

SUB: MATHEMATICS
LESSON NOTES-2
Ch-14: FACTORISATION

INSTRUCTIONS:
 IT IS MANDATORY TO WRITE ALL THE GIVEN NOTES IN THE MATH
CLASSWORK COPY.

 THE WORKSHEET PROBLEMS TO BE SOLVED IN THE CLASS COPY ALSO.

SUBTOPIC:
1. What is Factorisaion:-
An algebraic expression consists of variables, constants and operators. An
algebraic expression consists of terms separated by addition operation.

Consider the expression 3x(x+2). It can be written as a product of factors. 3,
x and(x + 2)

3x(x + 2) =3× x×(x + 2)

The factors 3, x and (x +2) are irreducible factors of 3x (x + 2).

Similarly, the expression 10x (x + 2) (y + 3) is expressed in its irreducible
factor form
as 10x (x + 2) (y + 3) = 2 × 5 × x × (x + 2) × ( y + 3).

Algebraic Expressions can be factorized using many methods. The most common methods
used for factorization of algebraic expressions are:

 Factorization using common factors

 Factorization by regrouping terms

 Factorization using identities
Let us discuss these methods one by one in detail:

 Method of common factors:-
 In order to factorize an algebraic expression, the highest common factors of the
terms of the given algebraic expression are determined and then we group the
terms accordingly. In simple terms, the reverse process of expansion of an
algebraic expression is its factorization.

 To understand this more clearly let us take an example.