Solve the simultaneous equations: 3x + 2y = 4 and 4x + 5y = 17

Step 1: multiply one or both equations so that the 2 equations have the same coefficient for either x or y (pick easier one) 5(3x + 2y) = 5(4) --> 15x + 10y = 20 AND 2(4x + 5y) = 2(17) --> 8x + 10y = 34 | Step 2: subtract one equation from the other 15x + 10y = 20 MINUS 8x + 10y = 34 --> (15x + 10y) - (8x + 10y) = 20 - 34 --> 7x = -14 | Step 3: solve the new equation 7x = -14 --> x = -2 | Step 4: substitute x = -2 into either one of our very first equations and solve to find y 3(-2) + 2y = 4 --> -6 + 2y = 4 --> 2y = 10 --> y = 5 | Step 5: check that our values for x and y are correct by substituting our values into the other initial equation

RD
Answered by Rania D. Maths tutor

4814 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

√ (6²+8²) = ∛(125a³) Find a.


Solve... 8x + 2 = 3x - 8


Here are the first four terms of a quadratic sequence: 11 26 45 68. Work out an expression for the nth term.


A semicircle has a diameter of 8cm, what it the area?


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