Expressions and manipulation
Lesson 3 of 13
Factorising
Objective. Factorise by taking out a common factor.
The key idea
Factorising is expanding in reverse: find the largest factor shared by every term and place it outside the bracket.
Worked example
Factorise 12x² + 18x.
- 1The highest common factor is 6x.
- 212x² ÷ 6x = 2x and 18x ÷ 6x = 3.
Answer: 6x(2x + 3)
Practice
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