How do I solve simultaneous equations?

2x + y = 7

3x - y = 8

You cannot find x and y using only one equations, but using both you can! So first you have use algebra to make both equations = y. Try this for the first equation by rearranging it.

This gives  y =7 - 2x

Now again for the second equation.

This gives y = 3x - 8

Now, because we can make these two equations equal, because they are both equal to y!

This gives 7 - 2x = 3x - 8

Now solve for x.

This gives 15 = 5x, so x = 15/5 = 3

Now that we know x, all we have to do it put in the value of x into one of the equations and solve it to get y!

y = 7 - 2x = 7 - 2*3 = 7 -6

y= 1 !

SO
Answered by Stephanie O. Maths tutor

2388 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Factorise the following expression: x^2-1


Which of these fractions is the largest - 33/56 ,4/7, 9/21, 6/14


A particle is moving along a straight line. The fixed point O lies on this line. The displacement of the particle from O at time t seconds is s metres where s = 2t3 – 12t2 + 7t(a) Find an expression for the velocity, v m/s, of the particle at time t.


ABC is a triangle with sides of length AB, 12m and BC,14m. Angle ACB = 43 degrees. Find the area of the triangle.


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