Solve the simultaneous equations 2a + b =4 and 5a – 3b = -1

When you solve normal equations like 4x-2=7, there is one equation and one unknown value. This case is no different: in order to solve these equations, you need to create one equation with one unknown. We start by labelling the equations 1 and 2. This method is called the substitution method. First we have to rewrite one of the equations, isolating one of the variables on one side. In this example, this is easiest with equation 1 (2a + b =4 --> b = 4 - 2a). We now have an expression for b, which we can substitute into equation 2. This gives 5a - 3(4 - 2a) = -1. We can then solve this new equation to give us 11a = 11, a = 1. We can then use a = 1 to find b, by substituting this value into one of the original equations. Using equation 1, we get 2(1) + b = 4, so b = 2, and a = 1.

MM
Answered by Molly M. Maths tutor

13923 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve the simultaneous equations 2x + 3y = 19 , 3x + y = 11


What is the value of x if 2X+1: 3 = 5: 9?


Solve the equation [(3x + 3)/2x] + 2x - 1 = -3


Q) The equation of a curve is y=(x+4)^2+7. Find the co-ordinates of the turning point


We're here to help

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

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences