The process of writing an expression as a product of two or more common factors is called method of factorisation. e.g.

In the above examples, are the factors of expression , are the factors of  and are the factors of .

            While solving the quadratic equation by the method of factorisation, we have the following steps:

• Convert the quadratic equation in standard form, if necessary i.e. ,    where
• Multiply coefficient of  with constant terms, we get .
• Now try to find two numbers whose products is  and sum or difference is equal to  (coefficient of ).
• Factorise the given expression on L.H.S.
• Equate each factor equal to zero.
• We get the required roots, say, .

 Example:
            Solve the equation by factorisation method.
                       
Solution:
            The given equation in standard form is 
                        
            Multiply coefficient ofand the constant term, we get
                        
            Divide  into two parts such that their difference or sum is

Possible factors of	Sum or Difference of factors
	(not possible)
	(not possible)
	(not possible)
	(possible)

Therefore,       
                        
                        
                        
                        
Either                  or  
                                  or