Class 8 Maths Factorisation Introduction

Introduction:

When we factorize an expression, we write it as a product of factors. These factors may be numbers,

algebraic variables or algebraic expressions. It can be used for many things, like helping perform

arithmetic operations.

Factors of a Natural Number:

Let us take a natural number 20

Now, 20 = 2 * 10 = 4 * 5 = 1 * 20

Thus, 1, 2, 4, 5 and 20 are the factors of the number 20.

A number written as a product of prime factors is said to be in the prime factor form.

Ex: 20 can be written as 2 * 2 * 5 is in the prime factor form.

Again the prime factor of 45 = 3 * 3 * 5 Factors of Algebraic Expressions:

We can express algebraic expressions as products of their factors.

Let us take an example. In the algebraic expression 2xy + 3y, the term

2xy can be written as:

2xy = 2 * x * y

In algebraic expressions, we use the word irreducible in place of prime. We say that 2 * x * y is the

irreducible form of 2xy.

Again 2xy(y + 5) = 2 * x * y * (y + 5)

So, the factors 2, x, y and (y + 5) are irreducible factors of 2xy(y + 5). .