Factorisation Lesson 4

Question 1

Bronze Example:

Factorise the following fully:

x2 - 17x - 60

Answer 1

First:

• 60
• 20 x 3

Second:

x2 - - 3x I -20x -60

Third:

x(x + 3) I -20(x + 3)

Finally:

(x-20) (x+3)

Question 2

Silver Example:

Factorise fully:

5x2 + 17x - 12
x2 - 16

Answer 2

First:

_________
(x + 4) (x - 4)

Second:

5x2 x -12 = -60

Third:

• 60
• 3x20

Fourth:

5x2 + 20x I -3x - 12

5x(x + 4) I -3(x + 4)

Fifth:

(5x - 3) (x + 4)
(x - 4) (x + 4)

Finally:

5x - 3
x - 4