1. ©G Dear 2008 – Not to be sold/Free to use
Mathematic
(Preliminary)
Basic Arithmetic
Factors
Grouping in Pairs
Stage 6 - Year 11
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©G Dear 2008 – Not to be sold/Free to use

2. a is common to both terms and can be put in front of brackets.
Factorisation
Simple Factors
ax + ay =
a( )
   
a is common to both terms and can be put in front of brackets.

3. x+y remains when the a is removed and are placed inside the brackets.
Factorisation
Simple Factors
ax + ay =
a(x + y)
    
x+y remains when the a is removed and are placed inside the brackets.
Example
15x - 24y =
3 x 5x - 3 x 8y
= 3(5x - 8y)

4. ax + ay + bx + by = a(x + y) + b(x + y) Factorisation
Grouping in Pairs
ax + ay + bx + by =
a(x + y)
+ b(x + y)
Examples
3x2 + x + 12x + 4 =
(3x2 + x) + (12x + 4)
= x(3x + 1) + 4(3x + 1) 
Note: 3x + 1 is the common factor
= (3x + 1)(x + 4)