Solve the simultaneous equations x^2 + y^2 = 9 and x+ y = 2. Give your answer to 2.d.p

Label your two equations 1 and 2 respectively. Make x the subject of the second equation, so x=2-y. Substitute x=2-y into x^2+y^2=9, to give (2-y)^2+y^2=9. Expand the brackets using FOIL to give 4-4y+y^2+y^2=9. By grouping like terms together get 2y^2-4y-5=0. Because the question asks for the answer in 2.d.p, you know to use the quadratic formula, so substitute into the given formula where a=2, b=-4 and c=-5 (dont forget the minus sign!). Using the + and the - sign you get y=2.87 and y=-0.87. Then substitute these values into x+y=2 to get x=-0.87 and x=2.87.

Answered by Georgia S. Maths tutor

30293 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Given 6x+2y=4 and 5x+y=8, solve the simultaneous equations to find x and y.


How do I use trigonometric ratios to work out lengths in right-angled triangles?


A ladder 5m long is leaning up against a wall. The foot of the ladder is 3m from the wall. How high up the wall does the ladder reach?


If a rectangle has area 48cm2 and sides length 6cm and (3x+2)cm, what is the value of x?


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