Solve the two simultaneous equations: 2y + x = 8 [A] and 1 + y = 2x [B]

I have labelled the two separate equations A and B so that it is easier to talk about them. There are two ways in which you can do these equations but I am going to explain the method using substitution. As y and x are in both of the equations we can try to eliminate at least one of these unknowns for the moment. So, if we rearrange [B] so that y=2x-1 we can then substitute this value of y into [A]. This will give us: 2(2x-1) + x =8. By multiplying this out we get: 4x-2+x=8 By grouping the x values together: 5x-2=8 Then placing all the unknowns to one side of the equation 5x=10 and then dividing both sides by 5 we get: x=2. So we have found the value for x! We would then substitute this into [B]: 1+y=2(2),then multiplying this out 1+y=4, placing all the unknowns onto one side: y=3 So we have a solution for y! Just to check that our answers are correct we can substitute our two values into [A]: 2(3)+(2)=6+2 =8 and 8 is the correct answer so we know our solutions are correct!

Answered by Ciara D. Maths tutor

6842 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

The formula v = u +at gives the final velocity of an object as it accelerates. If v= 35, a=4 and t=5 then find u


Solve the simultaneous equations: 6a + b = 16 and 5a - 2b = 19


How do I solve this linear equation? Angles A and B are in a quadrilateral are in ratio 2:3, angle C is 30 degrees more than angle B and angle D is 90 degrees.


How do you solve a simultaneous equation by 'substitution'?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences