Solve the simultaneous equations x + y = 2 and x^2 + 2y = 12

x+y=2 (1) x2+2y=12 (2) As we are dealing with x2 we’re going to have to use substitution to solve this set of simultaneous equations. From the first equation, we can rearrange to make y the subject: y=2-x (3)Now, we can substitute our new equation (3) into equation (2) to eliminate y: x2 + 2(2-x) = 12. By expanding we get: x2 + 4-2x = 12. To solve for x we need to make the equation equal to 0: x2-2x-8=0. To factorise, we need 2 numbers that multiply to make -8 and add to make -2; these 2 numbers are -4 and 2. Therefore x2-2x-8=0 is equal to (x-4)(x+2)=0. Solving for x we get x=4 and x=-2. We can now substitute these into our equation (3) to find y: y=2-4=-2 and y=2-(-2)=4. So our 2 pairs of answers are: x=4, y=-2 and x=-2, y=4

AK
Answered by Ayesha K. Maths tutor

5409 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

What is the gradient of a line with the equation y=4x+5?


x : y = 7 : 4, x + y =88. Work out the value of x - y.


How do you differentiate x^x?


f(x) = 5x − 12. (i) Calculate f(4). (ii) Find f( x + 1). Give your answer in the form ax + b .


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning