This study notes covers Worked Example 2: With Common Variable within Factorising for GCSE Mathematics. Revise Factorising in Algebra for GCSE Mathematics with 12 exam-style questions and 3 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 5 of 13 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Worked Example 2: With Common Variable
Factorise: 4x² + 10x
Step 1 Find HCF of numbers
HCF of 4 and 10 = 2
Step 2 Find common letters
x² has x×x, 10x has x
Common: x (lowest power)
Step 3 HCF = 2x
4x² ÷ 2x = 2x
10x ÷ 2x = 5
Final Write answer
4x² + 10x = 2x(2x + 5)
Practice questions for Factorising
Which is the correct factorisation of 6x + 15?
A student factorises x² + 5x + 4 as (x + 4)(x + 4). Explain why this is incorrect and give the correct factorisation.
Quick recall flashcards
Factorising
Take out highest common factor: 6x + 9 = 3(2x + 3)
Factorising Rule
Find the HCF of all terms (numbers AND letters), put outside bracket, divide each term for inside.