Factors in Algebra

It is important to know the four methods for finding factors that we use in algebra. These notes cover all four methods. they include guide number method for finding the factors of quadratic expressions, this method works for all quadratic expressions that have factors with whole numbers and does not require guessing or trial and error. Initially it may look complicated but that is because it includes explanations, once you get used to working this way it is quick and effective. It is a good idea to practice multiplying your factors together to check your answer and to help your understanding of factorising.

Tip: When factorising by grouping copy the first bracket and then work out what to put in front of it.

When factorising this

2cd – 2ca –3bd+ 3ab

factorise the first two terms

2c(d – a)

then repeat what is inside the bracket

2c(d – a)     (d– a)

then work out what should go in front of the bracket

2c(d – a) –3b(d– a)

finish by grouping the common factors

(2c–3b) (d –2a)

You are less likely to make mistakes with the signs when you do this.

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