Brainlag PlusTake out the highest common factor so the expression becomes a term times a bracket, and check by expanding.
Expanding backwards
Factorising undoes expanding.
Find the highest common factor of all the terms and write it outside the bracket.
- 6x² + 9x
- HCF of 6 and 9 is 3; both terms have an x
- = 3x(2x + 3)
- check: 3x × 2x = 6x², 3x × 3 = 9x
"Factorise fully" means nothing common is left inside: 2x(3x + 4.5) is not allowed, and 3(2x² + 3x) still has x in both terms.
The rest of this lesson and its 7 practice questions are in Plus.
Screen 1 of 3, free to read.
- 7 exam-style questions, marked as you go, each with a worked solution
- The Equation Solver beside every question
- Anything you get wrong is saved to your flashcards