How do you solve simultaneous equations?

I will run through an example of how to solve a set of simultaneous equations. In simultaneous equations you are given two or more algebraic equations and you need to solve them for the variables, usually called x and y. You start off by trying to get equivalent coefficients for either the x or y value in both of the equations.  For example: (1) 4x + y = 24 and (2) 7x + 3y = 47. Here we can multiply equation (1) by 3 so that both the x coefficients are equal to 3. So 3*(1) is equivalent to 12x + 3y =72. Now we can subtract (2) from 3*(1). This gives 5x + 0y = 25, giving 5x = 25 therefore x = 5. Substituting x back into equation (1) we get 4*5 + y =24. So y = 24 - 20 and y = 4. Giving us the solutions: x=5 and y=4.

Answered by Dorothy H. Maths tutor

2843 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

There are 10 boys and 20 girls in a class. The class has a test. The mean mark for all the class is 60. The mean mark for the girls is 54. Work out the mean mark for the boys.


Solve these simultaneous equations: 2x + y = 7, and 3x - y = 8. Do so by 1) Eliminating an Unknown and 2) Substitution.


Thomas wants to see how far he can throw a javelin. He records four of his throws as 45 metres, 40 metres, 55 metres, and x metres. Given that the mean of Thomas' throws is 50, determine the value of x.


How do you factorise x^2 - 4?


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