Expanding involves
removing the
brackets from an
equation
a(b+c) = ab + ac
1.06: Binomial Products
Binomial expressions
consist of 2 terms.
Binomial products are
two terms multiplied
by each other
(x+a)(x+b) = x^2 + bx + ax + ab
1.07: Special Products
Difference of two squares
(a+b)(a-b) = a^2 - b^2
Perfect Squares
(a+b)^2 = a^2 + 2ab + b^2
(a-b)^2 = a^2 - 2ab + b^2
Difference of two squares
(a+b)(a-b) = a^2 - b^2
Perfect squares
(a+b)^2 = a^2 + 2ab + b^2
(a-b)^2 = a^2 - 2ab + b^2
1.08: Factorisation
To factorise an
expression, we use the
distributive law in the
opposite way from
when we expand
brackets
ax + bx = x (a+b)
To factorise an expression, we use
the distributive law in the opposite
way from when we expand
brackets
ax + bx = x(a + b)
1.09 Factorising by grouping in pairs
If an expression has
4 terms, it can
sometimes be
factorised in pairs.
If an expression has 4
terms, it can sometimes
be factorised in pairs.
ax + bx + ay + by =
x(a+b) + y(a+b) =
(a+b)(x+y)
1.10 Factorising Trinomials
FInd the values for a and b so
that the sum a + b is the middle
term and the product ab is the
last term
x^2 + (a+b)x + ab = (x+a) (x+b)
1.11 Further trinomials
When the coefficient of the first term is not 1, for
example 5x^2 - 13x + 6 , we need to use a different
method to factorise the trinomial
This Method still involves finding 2
numbers that five a required sum and
product but it also involves grouping in
pairs.
For example, 5x^2 - 13x +6 = 5x^2
- 10x - 3x + 6 = 5x(x-2) - 3(x-2) =
(x-2)(5x-3)
First, multiply the coefficient of the first term by
the last term; 5 X 6 = 30. Now a + b = -13 and ab =
30. Since the sum is negative and the product is
positive, a and b must both be negative. 2
numbers with the product 30 and sum -13 are - 10
and -3. Now write the trinomial with the middle
term split into 2 terms, -10x and -3x, and then
factorise by grouping in pairs
1.12 perfect squares
You have to look at expanding
(a+b)^2 = a^2 + 2ab + b^2 and
(a-b)^2 = a^2 - 2ab + b^2. These
are perfect squares. When
factorising, use these results the
other way around