Solve X^2 +13X+48=12

It is first important to get the equation to equal 0, so to do this you minus 12 from each side of the equals symbol, giving you

X^2 +13X+36=0

Now it is time to think about factorising!

The best trick for this is to find two numbers that multiply together to make the number without any X's (36 in this case) AND add together to make the number with an X after it (13 in this case).

So start by listing the factors of 36 in pairs:






Then turn each into an addition






As 4+9 equal 13 we know that the two numbers in our brackets are 4 and 9! If we had not been able to make our number with addition, you could try with negative numbers (eg if our middle number was -5 we could make this by doing 4+-9=-5). Practice and knowing your times tables well will help you spot these easier.

So we factorise the equation into brackets


each bracket has to equal 0 so

X+4=0       X=-4

X+9=0        X=-9

Kemba M. 13 Plus  Maths tutor, GCSE Maths tutor, 11 Plus Maths tutor,...

5 months ago

Answered by Kemba, a GCSE Maths tutor with MyTutor

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


£18 /hr

Jessica K.

Degree: History (Bachelors) - Manchester University

Subjects offered:Maths


“Hi! I'm Jessica, and I am studing History at the University of Manchester. My interests in maths have developed following my studies at both GCSE and A-level. Over the years of these studies I attended many tutoring sessions to help d...”

MyTutor guarantee

£18 /hr

Karishma D.

Degree: Medicine (Bachelors) - Imperial College London University

Subjects offered:Maths, Chemistry+ 3 more

-Personal Statements-
-Medical School Preparation-

“Hi guys, I'm a first year medical student at Imperial College London. I chose this degree because it indulges my passion for science whilst allowing me to interact with people, putting what I learn in the lecture theatre into practise...”

£18 /hr

Jack S.

Degree: Mathematics (Masters) - Exeter University

Subjects offered:Maths, Further Mathematics

Further Mathematics

“I am a 4th year student at the University of Exeter studying mathematics. I have taught at both GCSE level and 1st year university level maths.”

MyTutor guarantee

About the author

Kemba M.

Currently unavailable: for new students

Degree: Architecture (Bachelors) - Sheffield University

Subjects offered:Maths, History+ 2 more

Graphic Design
-Personal Statements-

“About me: Hello! I'm Kemba and I'm a first year undergraduate Architecture student at the University of Sheffield. I have a passion for three main subjects: History, Maths and Graphic Design, although I'm not studying any of these top...”

You may also like...

Posts by Kemba

Help, I have designers block!

How should I approach my GCSE maths paper?

How would I structure an essay?

Solve X^2 +13X+48=12

Other GCSE Maths questions

Make x the subject of this equation: y= 2(1-x)/(3x-1)

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

Work out the value of 125^(-2/3)

These are the selling prices of 5 houses in 2007: £145 000, £170 000, £215 000, £90 000, £180 000. Work out the mean selling price.

View GCSE Maths tutors

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