MYTUTOR SUBJECT ANSWERS

415 views

Solve this pair of simultaneous equations (1) 5x+2y=20 and (2) x+4y=13

To solve these equations, our aim is to find a value of x and a value of y that satisfy both equations at the same time. By satisfy we mean, if we plug our values in for x and y then the left hand side and right hand side of each equation will equal eachother.

First to find x and y we must try and eliminate either x or y to find the other.

Lets try and eliminate x.

We can write equation (2) with x as the subject by subtracting 4y from both sides, like so:

x=13-4y

Now we can substitute this into equation (1) to eliminate x giving:

5(13-4y) + 2y = 20

Expanding the brackets gives

65 - 20y + 2y = 20

Now we collect all the y's onto one side and the constants onto the other giving:

45 = 18y

Then divide through by 18 to give y=5/2

Now we substitute this into either equation (1) or (2) for y to find x.

With (1) : 5x + 2(5/2) = 20, 5x = 15, x=3

With (2) : x + 4(5/2) = 13, 5x=15, x=3

So our solution is x=3, y=5/2. It isn't necessary to show x's value with both equations but it can be useful to check your answer is correct!

Jenny H. A Level Maths tutor, GCSE Maths tutor

11 months ago

Answered by Jenny, a GCSE Maths tutor with MyTutor


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

780 SUBJECT SPECIALISTS

£22 /hr

Eleanor H.

Degree: Biochemistry (Bachelors) - Bristol University

Subjects offered:Maths, Chemistry+ 1 more

Maths
Chemistry
Biology

“ABOUT ME: I am a biochemistry student, currently studying at the University of Bristol, and have had a passion for the natural sciences from a very young age. I am patient, hardworking and experienced, having tutored students in Maths...”

£20 /hr

Bea A.

Degree: MMath Pure Mathematics (Masters) - St. Andrews University

Subjects offered:Maths, English Literature

Maths
English Literature

“I am an experienced mathematician with a personal approach to tutoring. I'm here to help you further your mathematical potential.”

£18 /hr

Dan W.

Degree: Economics and Accounting (Bachelors) - Bristol University

Subjects offered:Maths, Economics

Maths
Economics

“I achieved top grades whilst juggling cricket at a high level. I’ve tutored for Young Einstein Tuition & been a Peer Mentor to those facing personal issues”

About the author

£18 /hr

Jenny H.

Degree: Economics and Mathematics (Bachelors) - Bristol University

Subjects offered:Maths

Maths

“I'm an Economics and Mathematics student at the University of Bristol. Maths has always been one of my passions, I enjoy learning new areas of the field and encouraging others to have the same enthusiam for the subject as I do. I hope ...”

MyTutor guarantee

You may also like...

Posts by Jenny

How do I differentiate y=(4+9x)^5 with respect to x?

Solve this pair of simultaneous equations (1) 5x+2y=20 and (2) x+4y=13

Other GCSE Maths questions

What is 45% of 60?

Find the inverse of y = 2x+1/ x-1

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

Solve 3x^2 + 5x +2

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