How do I solve two simultaneous equations?

Supposing we have two equations x+2y=5 and 3x-y=10 and we want to find x and y we can use the following techinque. Multiply both the RHS and the LHS of the second equation by 2, giving us 6x-2y=20. Then add this to the first equation, giving us 7x=25 thus x=25/7. The substitute the value for x to find y: 25/7 +2y=5 => y=5/7. Alternatively, we can manipulate the first equation to give us x=5-2y and substitute in the second equation: 15-6y-y=10 => -7y=-5 =>y=5/7 and then substitute in the first equation to find x. Remember, to find the value of n variables we need n equations, except in special cases.

Answered by Theano X. Maths tutor

3203 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

The value of a car depreciates by 35% each year. At the end of 2007 it was £5460. Work out the value of the car at the end of 2006.


2x^2 - 16x + 32


why does 4 / 0.5 =8?


Solve these simultaneous equations: y=3x-10; y=2x+5


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