A circle with centre C has equation x^2 + y^2 + 2x - 6y - 40 = 0. Express as (x - a)^2 + (y - b)^2 = d.

First we must complete the square on both x and y. To complete a square we must take the number before the x and half it, for example nx we get n/2. We then write it as (x + n/2)- (n/2)2

So for our question we have 2x so we will write (x + 1)2 - (1)2. Then we repeat for y. We have -6y so we will write (y - 3)2 - (3)2.

We then write all of this together as (x + 1)2 - 1 + (y - 3)2 - 9 - 40 = 0. Rearrange and we get (x + 1)+ (y - 3)2  = 50

Answered by Reuben M. Maths tutor

6720 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve the simultaneous equations, 2x-3y=14 and 3x+4y=4


What is the best way to revise for my Maths GCSE?


Re-arrange [4x+ 9t + 8s= 3g] to make x the subject of the formula


Given the function f(x) = 2x^2 + 3.When f(x) = 53 find both values 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 2013–2024

Terms & Conditions|Privacy Policy
Cookie Preferences