MYTUTOR SUBJECT ANSWERS

520 views

Factorise and solve x^2 - 8x + 15 = 0

The question gives you a hint on how to go about this question - Factorise!!

1) Factorise the left hand side. Find the two numbers which will add to give -8 and multiply to give 15. In this case, -3 and -5. 

(x-3)(x-5)=0

2) Each set of brackets can equal 0. If a multiplication is equal to 0, then at least one term must be 0 itself. 

x-3=0, x-5=0

3) Solve the equations. 

x=3 or 5

4) CHECK!! Plug your values of x into the original equation to make sure you are right - an easy way to stop making silly mistakes! 

When x=3, 32-(8x3)+15 = 9-24+15=0  (correct)

When x=5, 52-(8x5)+15 = 25-40+15=0 (correct)

 

Kieran N. GCSE Maths tutor, GCSE History tutor, GCSE Spanish tutor

1 year ago

Answered by Kieran, a GCSE Maths tutor with MyTutor


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

464 SUBJECT SPECIALISTS

Katrina M. IB Maths tutor, 13 Plus  Maths tutor, GCSE Maths tutor, A ...
£18 /hr

Katrina M.

Degree: Mathematics Bsc (Bachelors) - Exeter University

Subjects offered:Maths, Physics+ 2 more

Maths
Physics
Further Mathematics
-Personal Statements-

“Hi, I am a patient, experienced and enthusiastic tutor ready to help each student reach their full potential.”

£24 /hr

Sioned D.

Degree: Law (Bachelors) - University College London University

Subjects offered:Maths, History+ 4 more

Maths
History
English
Biology
.LNAT.
-Personal Statements-

“Hello! I'm a University College London Final year Law Student with a great deal of tutoring experience in English, Maths, Sciences and Entrance Exams. ”

£22 /hr

Emma J.

Degree: Medicine (Bachelors) - Cambridge University

Subjects offered:Maths, Chemistry+ 4 more

Maths
Chemistry
Biology
-Personal Statements-
-Oxbridge Preparation-
-Medical School Preparation-

“Hi! I'm Emma and I'm studying Medicine at Cambridge. I love the sciences, and hopefully through my passion I can help you get the grade you want! ”

About the author

Kieran N.

Currently unavailable: for regular students

Degree: Spanish and History (Bachelors) - Southampton University

Subjects offered:Maths, History

Maths
History

“About Me I am a first year student at the University of Southampton, studying Spanish and History. Although I eventually chose to follow humanities, I was always split as to what I prefered - at A Level I was so unsure I ended up taki...”

MyTutor guarantee

You may also like...

Posts by Kieran

Factorise and solve x^2 - 8x + 15 = 0

How do I analyse a source?

What is the subjunctive and when should it be used?

Other GCSE Maths questions

Rationalise 1/(√7) ?

1/4 of a number is 20. What is 5 times the number?

How do I find the equation of a straight line?

Simplify (x^2-9)/2x^2+5x-3

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

mtw:mercury1:status:ok