Solve the simultaneous equations, 5x + 2y = 20 , x + 4y= 13

(Equation 1) 5x + 2y = 20 (Equation 2) x + 4y= 13
As we know the values for x and y are the same in both equations, we can use them to find out the values for both, In order to do this we need to take one equation and define it by either x or y, for example taking equation 2 and definining x in terms of y by rearranging the equation.
x + 4y = 13
x= 13 - 4y
Now we have x defined in terms of y we can put this into equation 1 and simplify to get a value for y.
5x + 2y = 20
5(13-4y) + 2y = 20
65 - 20y +2y = 20
65 - 18y = 20
-18y = -45
18y = 45
y = 2.5
Now that we have a value for y we can use that for find x. If we put our value for y into equation 2
x + 4y = 13
x + 4(2.5) = 13
x + 10 = 13
x = 3
Now we have our two values for x and y we have solved the simultaneous equations, to check they're correct we should substitute both values into either equation and see if the equation is correct.

Answered by Ellen C. Maths tutor

11351 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve for x: 2x^2 = 5x + 12


How do I know when to use sine, cos or tan when working with right angled triangles?


Yesterday it took 5 cleaners 4 and ½ hours to clean all the rooms in a hotel. There are only 3 cleaners to clean all the rooms in the hotel today. How much time will it take them?


Express 300 as a product of its prime factors.


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