Factorise fully 27x^2 - 3

First, work out what number is a common factor of both terms - in other words what number 'goes into' both 27 and 3? 3 is a factor of both so put 3 outside the bracket. = 3( __ - __) Now work out what goes in each of the gaps inside the bracket - what do you need to multiply by 3 to get 27x2 ? What about to get - 3 ? = 3(9x2-1) But make sure you don't stop there! We need to factorise the expression inside the bracket, to make sure we have done what the exam question asked and factorised 'fully'. You may recognise that this expression looks familiar - it is the difference of 2 squares because there is no x term, only an x2 and a number. So we know the factorised version must look like this: =3(_x + _)(_x - _) To find the missing numbers we just need to work out what multiplies by itself to make 9 & what multiplies by itself to make 1. = 3(3x+1)(3x-1)

Answered by Rebecca T. Maths tutor

3426 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Bag A contains £7.20 in 20p coins. Bag B contains only 5p coins. The number of coins in bag B is three-quarters of the number of coins in bag A. How much money is in bag B?


(This was taken from a GCSE past paper)A bag of 24 spoons costs £19.95. A box of 18 forks costs £15.55. Bags and boxes cannot be split. Gregor decides to buy the same number of spoons as forks. He places an order to buy the smallest number of each


Solve the quadratic: 3x^2+4x = 20 to find x.


How do I draw a pie diagram?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences