FACTORISATION OF QUADRATIC EXPRESSION

Factorisation is the process of expressing an algebraic expression as a product of two or more algebraic expression. By doing this, we would know what needs to be multiplied to be able to get the expression.

In secondary 1, we have learnt about the factorization of linear expressions. The first way of factorizing the expression would be by looking for the common factor and taking it out. An example would be:

44b2+33ab


For the above expression, we can see that there is a common factor of b and 11. So, we would have to take it out of the expression.

44b2+33ab

= 11b(4b+3a)

Thus, we can see that the factorized form of 44b2+33ab is 11b(4b+3a).


Another example would be

-3a(2+b)+18a(b-1)

(taken from Shinglee Math TB)

For the example above, we would first have to expand and simplify the expression before factorizing the common factor out. The solution would be:

-3a(2+b)+18a(b-1)

= -6a-3ab+18ab-18a

= -24a-3ab+18ab

= 18ab-24a-3ab (expanded and simplified answer)

18ab-24a-3ab

The common factor here is 3 and a. We would have to factor that out.

18ab-24a-3ab

= 3a(6b-8-b)

= 3a(5b-8)

Thus, the factorized form of 18ab-24a-3ab is 3a(5b-8).

Now, after learning quadratic expressions, we have learnt new ways to factorize our expressions. Let us watch this video which explains of the different factorizing methods that could be used for quadratic expression.