Solve the simultaneous equations x+y=8 and 3x-y=4.

Notice that y has the same coefficient (ignoring the sign) in both equations. So, we will use the elimination method. The elimination method means that we will combine the two equations to eliminate the y variable, allowing us to find the value of x. Then, we will substitute this value of x in order to find y.Since y has opposite signs in the two equations, we will eliminate y by adding the equations. Adding gives (x+y) + (3x-y) = 8 + 4. Simplifying gives us 4x = 12 so x = 3. Now, by substituting x = 3 into x + y = 8 we get that 3 + y = 8 so y = 5. Hence we have solved our simultaneous equations and have that x = 3 and y = 5.

Answered by Fiona S. Maths tutor

4768 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

What is 25% of 400?


How do I expand out a pair of brackets?


Factorise fully the following: 12x^3 + 3x^2 + 15x


A kettle costs £50 in a sale. It was reduced by 30%. What was the original price of the kettle?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences