If 2x + y = 13 and 3x - y = 12, what are the values for x and y?

To solve these simulataneous equations we need to use substitution:If 2x + y = 13 then y = 13 - 2xTherefore 3x - y = 12 can be rewritten as 3x - (13 - 2x) = 12We can expand these brackets and solve for x:3x - 13 + 2x = 12-> 5x = 25--> x = 5Now we have the value of x, we can subsitute this into either of the initial equations to find the value of y:2(5) + y = 13--> 10 + y = 13--> y = 3OR:3(5) - y = 12--> 15 - y = 12--> y = 3You can then check your values are correct by subsituting them into either of the equations:2(5) + (3) = 1310 + 3 = 13 --> it works!

EW
Answered by Emma W. Maths tutor

13014 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Why is the area of a triangle 1/2 * b * h?


There are 11 counters in a bag. 8 of them red, 3 of them green. Neville takes 2 counters from the bag. Work out the probability that Neville takes one counter of each colour.


The equation of the line L1 is y = 3x – 2 The equation of the line L2 is 3y – 9x + 5 = 0 Show that these two lines are parallel.


How do I a differentiate a cosine function?


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