Solve the following simultaneous equations to obtain values for x and y: 2x + y = 7 & 3x - y = 8.

Label your equations 1 and 2 respectively. Make y the subject of equation 2 by taking away 3x from both sides and multiplying both sides by -1, to get y = 3x - 8. Now substitute this into equation 1 (i.e. replace the 'y' in equation 1 with '3x - 8'), giving 2x + (3x - 8) = 7. By grouping like terms together and adding 8 to both sides we get 5x = 15. Now to obtain our value of x simply divide both sides by 5, hence x = 3. Now use this value of x to find y. Substitute x = 3 into equation 2. So 3(3) - y = 8. This gives 9 - y = 8. By subtracting 9 from both sides and multiplying both sides by -1, we can get our value of y, giving y = 1. 

Answered by Pratham M. Maths tutor

2885 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Frank, Mary and Seth shared some sweets in the ratio 4:5:7. Seth got 18 more sweets than Frank. Work out the total number of sweets they shared.


Solve algebraically the simultaneous equations 2x+y=5 and 3x+y=7, for x and y.


Lisa, Max and Punita share £240 in the ratio 3 : 4 : 8 How much more money than Lisa does Punita get?


What does differentiation mean and represent? (A-Level students)


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