1. EXPANDING DOUBLE BRACKETS

2. The area of a rectangle that has sides of length (x + 5) and (x + 2)
can be found by splitting the rectangle into four parts.
x + 5 x 2 5 x2 5x
x + 2 2x 10 So

3. You can multiply double brackets without using a diagram.
To expand double brackets you multiply each term in the first bracket by each term in the second bracket.
Use the mnemonic FOIL to help you. F L
F first
O outside
I inside
L last I O

12. Solving problems

13. x + 7
1 The shaded area is 40 cm2.
Find x. x
x + 3 x
rectangle – square = 40
expand the brackets
simplify
take 21 from both sides
divide both sides by 10

14. 2 Find x for this right angled triangle.6
Use Pythagoras x
expand the brackets
take x2 from both sides
take 1 from both sides
divide both sides by 2

15. 3 Write down and simplify an expression for
the surface area of the cuboid.
x + 2 x
x + 5
surface area = sum of areas of the six faces
expand the brackets
simplify