Solve the simultaneous equations 2x + 7y = 15 and 3x + 6y = 21

Find the lowest common multiple of 2 and 3, which is 6. Multiply each term in the first equation by 3, and each term in the second equation by 2 to produce two equations with the same coefficient of x (which is 6). The two resulting equations are 6x + 21y = 45 and 6x + 12y = 42. Now you need to cancel the x term by subtracting the second equation from the first which leaves you with 9y = 3, y =1/3. Now sub y=1/3 into any of the four equations to find an x value of 19/3.
Copy of method worked through ready to show in session

IR
Answered by Isobel R. Maths tutor

2911 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How could you sketch a graph for y=x^2-10x+21?


Write x² + 4x -16 = 0 in the form (x+a)² - b = 0. Solve the equation giving your answer in surd form as simply as possible.


Solve the simultaneous equations: 5x + y = 21 and x - 3y = 9


x^2-9x+20=0


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