# Factorisation using Identities

The standard identities are

Using these identities we will do the following examples.

Â

Example

Factorise:

Solution

From the above expression, it has three terms and the terms are positive. Using identity (I)

Â

Example

Factorise

Solution

The above expression has 3 terms and the middle term is negative. Here

By identity (ii)

Â

Example

Factorise: .

Solution

There are two terms both are squares and the second term is negative. The expression is of the form

By identity III

Â

Example

Factorise

Solution

Â

Example

Factorise

Solution

Now, cannot be factorised further, but is factorisable by identity III