MYTUTOR SUBJECT ANSWERS

351 views

How to factorise quadratic equations?

When factorising quadratics there's a special order that will always make it a lot easier!

First, Outside, Inside, Last! 

FOIL.

This is what I still use to remember how to multiply out brackets. 

If we start with an easy example and follow the FOIL method:

(x + 1)(x - 1)

First: x*x = x2

Outside: -1*x = -x

Inside: 1*x = x

Last: -1*1 = -1

 

Now, we have the results for each of our letters of FOIL. We take these answers and put them together in one line, by adding them all together.

 

x2+ (-x) + x + (-1)

If we look at this equation we can see that x squared is alone so can remain. However (-x) + x results in a value of 0 therefore we remove both of these xs as they have now cancelled each other out. 

As we pay attention to signs we see that we have (-1). If we are using addition on towards a negative number the addition is then replaced with subtraction.

 

Therefore our final result will be

 

x- 1.

Lydia B. GCSE Maths tutor, A Level Maths tutor

2 years ago

Answered by Lydia, a GCSE Maths tutor with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist

327 SUBJECT SPECIALISTS

£18 /hr

Ellen K.

Degree: Modern Languages and Cultures (Other) - Durham University

Subjects offered: Maths, German+ 1 more

Maths
German
French

“Hi, I'm Ellen and I'm studying Modern Foreign Languages and Cultures at Durham University. I achieved 3 As in my A-Levels in Maths, French and German. I have lots of experience working with children as I volunteered for several years a...”

MyTutor guarantee

£18 /hr

Thea H.

Degree: Health and Human Sciences (anthropology) (Bachelors) - Durham University

Subjects offered: Maths, Science+ 1 more

Maths
Science
French

“About Me! I am an Anthropology student at Durham University where I also study french and portuguese. I have always had a passion for languages and would love to help someone else  achieve their goals (whether or not you share my pass...”

MyTutor guarantee

£22 /hr

Nathan L.

Degree: Materials Science (Masters) - Oxford, St Edmund Hall University

Subjects offered: Maths, Physics+ 1 more

Maths
Physics
Chemistry

“About Me: I'm a first year Materials science undergraduate at The University of Oxford. I loved learning about science and maths at school and hope my tutorials make you feel the same.  Structure: The key concept about tutorials i...”

About the author

£18 /hr

Lydia B.

Degree: Mathematics (Bachelors) - Exeter University

Subjects offered: Maths

Maths

“Top tutor from the renowned Russell university group, ready to help you improve your grades.”

MyTutor guarantee

You may also like...

Other GCSE Maths questions

Find the possible values of x when x^2+8x+15=0

Whats the inverse of y = 2x+1/x-1 ?

How would I solve this set of simultaneous equations using the elimination method?

Expand and simplify (5x – 2y)(3x – 4y)

View GCSE Maths tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok