Factorising is the reverse of multiplying out brackets.

We put an expression into brackets by taking out the highest common factor (HCF) of each term in the expression.

To work out what goes inside the brackets, we divide each term by this HCF.

Example

Factorise fully 10x - 15

Answer

The HCF of 10x and 15 is 5.

So we take 5 outside the brackets and divide each term by 5 to work out what goes inside the brackets.

The answer is 5(2x - 3)

We can check it to make sure that it works by multiplying out the brackets again!

5 x 2x = 10x

5 x -3 = -15

So we get 10x - 15 which is correct!!

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