How do you solve simultaneous questions?

When an equation has two or more variables, for example and x and y, more than one equation is need to solve it.  The number of equations needs is equal to the number of variables you have.  For example, if you need to find x and y, 2 equations will be needed. There are multiple ways you can solve simulataneous equations, through substitution, elimination and graphically. Let's consider the first method, substitution.

Here are two example simultaneous equations:

  1. x + y  = 13

2)  2x + 5y = 56

Rearranging equation 1 to give x or y explicitly:

  1. x = 13 - y

Substituting

  1. into 2)

  2. 2(13 - y) + 5y = 56

Expand and solve  

26 - 2y + 5y = 56

3y = 30 y = 10

Using equation 3)

x = 13 - y

  = 13 - 10   = 3

ES
Answered by Elise S. Maths tutor

3541 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Use integration by parts to integrate ∫ xlnx dx


I don't understand chain rule for differentiation especially when combined with more complex functions.


Differentiate and find the stationary point of the equation y = 7x^2 - 2x - 1.


A curve has parametric equations -> x = 2cos(2t), y = 6sin(t). Find the gradient of the curve at t = π/3.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning