MYTUTOR SUBJECT ANSWERS

366 views

How do I solve the simultaneous equations 5x - 3y = -1 and 3x + y = 5?

One method of solving these is by elimination. We can try to subtract a multiple of one equation from the other to cancel the x's (or y's).

5x - 3y = -1 (A)
3x + y  = 5  (B)

In this case, we can add 3*(equation B) to equation A to cancel the y's. We get

14x = 14, so x = 1.

To find y, substitute this value of x into one of the original equations and solve for y.

5 - 3y = -1 (A, sub x = 1)
6 - 3y = 0
     3y = 6
      y  = 2

So the answer is x = 1, y = 2. It's a good idea to check your answer using the other equation (the one you didn't substitute into before).

3x + y = 5 (B)
 3  + 2 = 5 (sub x = 1, y = 2)

The last equation is clearly true, so we have in fact found the correct x and y.

Alex K. GCSE Maths tutor, A Level Maths tutor

8 months ago

Answered by Alex, a GCSE Maths tutor with MyTutor


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

436 SUBJECT SPECIALISTS

£20 /hr

Oliver W.

Degree: Natural Sciences (Bachelors) - Cambridge University

Subjects offered: Maths, Extended Project Qualification+ 4 more

Maths
Extended Project Qualification
Economics
Chemistry
Biology
-Personal Statements-

“I am third year student at the University of Cambridge studying Natural Sciences. I specialise in Neurobiology. However, I have a lot of experience in othersciences and maths, at GCSE and IB level. I studied for 5 years at Sevenoaks Sc...”

£18 /hr

Quentin D.

Degree: Structural Engineering with Architecture (Bachelors) - Edinburgh University

Subjects offered: Maths, Science+ 2 more

Maths
Science
Physics
French

“Hello! My name is Quentin Dorleans and I am a french IB graduate currently in my first year of studying Engineering at the University of Edinburgh. I am not a big study fan, and being extremely sporty myself I totally understand those ...”

MyTutor guarantee

£18 /hr

Philip C.

Degree: Mechanical Engineering (Masters) - Imperial College London University

Subjects offered: Maths

Maths

“About me: I am a 4th year Mechanical Engineering student at Imperial College London. I have studied Mathematics across all levels and use it on a daily basis during my degree. I am extremely passionate about helping others gain a deep...”

MyTutor guarantee

About the author

Alex K.

Currently unavailable: until 24/06/2016

Degree: Mathematics (Masters) - Cambridge 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...

Posts by Alex

How do I solve the simultaneous equations 5x - 3y = -1 and 3x + y = 5?

If y = 5x^3 - 2x^2 + 2, what is dy/dx?

Other GCSE Maths questions

Simplify (3x^2 - 15x)/(3x^2 - 13x -10)

Amy, Beth and Colin share 36 sweets in the ratio 2 : 3 : 4. Work out the number of sweets that each of them receives.

Q: How to solve the simultaneous equations 3x+2y=7 and 5x+y=14

Factorise X^2 + 1X -12

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