MYTUTOR SUBJECT ANSWERS

92 views

Solve the simultaneous equations (with a calculator)

x^2 + y^2 = 9

x + y = 2 

1) Firstly look at the second equation which is the simplest and think how you can rearrange it to fit into the first equation:

x + y = 2  can be rearranged to y = 2-x 

2) y = 2-x can then be substituted into the first equation, and 'gets rid of' the y in the process! Check it out:

x^2 + (2-x)^2 = 9 

3) now expand the brackets:

x^2 + (2-x)(2-x) = 9 

x^2 + 4 -2x -2x + x^2 = 9 

2x^2 -4x + 4 = 9 

4) Now if we can 'move the 9 over the equals sign', we will have an equation that equals zero.  This looks like a quadratic equation! 

2x^2 -4x - 5 = 0 

5) Always think 'factorise!' whenever presented with a  quadratic.  However this doesn't work in this case, so we are going to have to use the quadratic formula!

Try it and see! 

The answer is:

x = 2.87 and y = -0.87

or 

x = -0.87 and y = 2.87

TIP: always check your answer when you can (put the values back into the orignial equations

This question is a grade A* so don't worry if it seems difficult (I will be more than happy to go through simpler questions and then try and build up your  confidence from there!)

Emily G. GCSE Physics tutor, A Level Geology tutor, GCSE Geography tu...

2 months ago

Answered by Emily, a GCSE Maths tutor with MyTutor

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

327 SUBJECT SPECIALISTS

£18 /hr

Jasmine S.

Degree: Mathematics (Bachelors) - Exeter University

Subjects offered: Maths, Physics+ 1 more

Maths
Physics
Further Mathematics

“Hi, I'm Jasmine and I'm a second year Mathematician at Exeter University, I'm looking to help students prepare for their Maths and Physics exams.”

£20 /hr

Venetia L.

Degree: General Engineering (Masters) - Durham University

Subjects offered: Maths, Further Mathematics

Maths
Further Mathematics

“About Me: I study General Engineering at the University of Durham. I have always enjoyed the maths and science subjects, and hope to help students who also share my love for them too! I have experience in working with young pupils and...”

£18 /hr

Amilah C.

Degree: Physics with a year abroad (Masters) - Edinburgh University

Subjects offered: Maths, Physics+ 1 more

Maths
Physics
Chemistry

“Hi there, welcome to me page! About Me: I am currently studying Physics at the University of Edinburgh. From a young age, science has always been a passion of mine, and hopefully I can convey this in my tutorials. Previously, I found...”

About the author

£18 /hr

Emily G.

Degree: Geology (Masters) - Imperial College London University

Subjects offered: Maths, Physics+ 2 more

Maths
Physics
Geology
Geography

“Do you want help with Maths, Physics, Geology or Geography? Or desperately need a dedicated tutor to mentor you through writing your personal statement? Look no further! I’m Emily, studying Geology atImperial College London and wish t...”

MyTutor guarantee

You may also like...

Other GCSE Maths questions

Whats the difference between the three main trigonometric functions?

How do I solve the Hannahs sweets question from the 2015 GCSE paper?

How do I simplify the equation 4x + 5x -2 - 2x + 7?

Express 4/(2-√2) in the form a+b√2 and write down the values of a and b.

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