factorisation-student-250803131347-67d83200.ppt

slides on factorization

1. FACTORISATION

2. Common Factors
The first thing to check when
factorising is common factors
Example 1:Factorise 3a + 12b

3. 3a + 12b
Look at the numbers. What
is the highest number that
divides evenly into both 3
and 12 ?
Step 1 :
Step 2 :Are there any variables
common ?
3
Not this time

4. Now that we have established that 3
is the highest common factor (HCF),
we put this outside the bracket, so
3a + 12b = 3( + )
What do I
need to
multiply 3
by to get
3a ?
a
What do I
need to
multiply 3
by to get
12b ?
4b

5. Example 2 : 14ab + 18ac
Look at the numbers. What is
the highest number that
divides into both 14 and 18 ?
Step 1 :
Step 2 :Are there any variables
common ?
2
Yes, a

6. Now that we have established that 2a
is the highest common factor (HCF),
we put this outside the bracket, so
14ab + 18ac = 2a( + )
What do I
need to
multiply 2a by
to get 14ab ?
7b
What do I
need to
multiply 2a
by to get
18ac ?
9c

7. Factorise:
Example 3 :
Example 4 :

aba2418
2

xx515
3


8. Solutions:
)43(62418
3 Example
2
baaaba 
)13(5515
4 Example
23
 xxxx

9. Now try the questions in
Set A on the worksheet

10. Difference of Perfect Squares
DOPS
Each of the following is an example of
a perfect square.
Numbers: 1, 4, 9, 16, 49, 81, 121
Variables:
6422222
,,,,,, yxyxtba

11. Example 1:Factorise 16
2
a
)4)(4(16
2
 aaa
Note that the first
term in each bracket
is the same
One bracket has
+ the other –
Note that the second
term in each bracket is
the same and it is 16

12. Solution:
)9)(9(81
2
 ppp
81
2
pExample 2:Factorise

13. Solution:
)1()1(1
2
ttt 
Example 3: Factorise
2
1t

14. Solution:

)32)(32(94
2
 kkk
Example 4 :Factorise 94
2
k
Note that the second
term in each bracket is
the same and it is 9
One bracket has
+ the other –
Note that the first term
in each bracket is the
same and is
2
4k

15. Solution:
)5)(5(25
22
gmgmgm 
Example 5: Factorise
22
25 gm

16. Complete Set B questions
on the worksheet

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