1. MATHEMATICS
From 3
Factorization of

2. Introduction
Objectives: Encouraged to practice thinking skills such as ‘trial and error’ or ‘use equations’.
Target: After the lesson, students should be able to do simple factorization.
Duration: 30 mins.

3. Introduction Target group: Form 3 students.
Assumption: Students are expected to know how to solve simple linear equations.

4. What shall we get when we
expand ?

5. What shall we get when we
expand ?
+ qx

6. What shall we get when we
expand ?
+ qx
+ px

7. What shall we get when we
expand ?
+ qx
+ px
+ pq

8. What shall we get when we expand ?
Simplify by taking the x out.
+ qx
+ px
+ pq

9. What shall we get when we expand ?
Answer :
+ (p + q) x
+ pq

10. Consider this example
Expand :
(x + 2)( x + 3)

11. Consider this example
Expand :
(x + 2)( x + 3)
+ 3x

12. Consider this example
Expand :
(x + 2)( x + 3)
+ 3x
+ 2x

13. Consider this example
Expand :
(x + 2)( x + 3)
+ 3x
+ 2x
+ 2x3

14. Consider this example Expand : (x + 2)( x + 3) + 3x + 2x + 2x3
Again, simplify by taking the x out.
+ 3x
+ 2x
+ 2x3

15. Consider this example Expand : (x + 2)( x + 3) + (2 + 3) x + 2x3
Therefore the answer is
+ (2 + 3) x
+ 2x3

16. (x + 2)( x + 3) + (2 + 3) x + 2x3 = + (p + q) x + pq =
Compare with the previous example
+ (2 + 3) x
+ 2x3 =
(x + 2)( x + 3)
+ (p + q) x
+ pq =

17. EASY!! Now, what are the answers for the following expression ?
(x+4)(x+7) = x2+ ( ? )x + ( ? )
The answer is
EASY!!
(x+4)(x+7) = x2+ ( )x + ( ) 11 28
4x7
4+7

18. To do it the other way round is harder. Can you do this?
= (x + ? ) (x + ? )
The answer is
= (x ) (x ) 2 5
2 x 5
2 + 5

19. Steps to factorize :
= (x + ? ) (x + ? )
Fist draw two brackets

20. Then consider the factors of 10
Steps to factorize :
= (x + ? ) (x + ? )
Then consider the factors of 10
That is : 1 x 10 or 2 x 5

21. WRONG = (x + ? ) (x + ? ) = (x + ) (x + ) 1 Steps to factorize :
Try 1 and 10
= (x ) (x ) 1 10
WRONG
1+10 is not equal to 7
therefore this is...

22. CORRECT = (x + ? ) (x + ? ) Try 2 and 5 = (x + ) (x + ) 2
Steps to factorize :
= (x + ? ) (x + ? )
Try 2 and 5
= (x ) (x ) 2 5
2+5 is equal to 7
therefore this is...
CORRECT

23. Interesting web-sites containing materials of factorization.

24. THE END