SOLUTION: Hi, I am trying to find the center and radius of this circle. I thought I had it until I tried to factor it, so I appreciate any help! {{{3x^2+3y^2-6x+12y=0}}} This is what I

Algebra ->  Circles -> SOLUTION: Hi, I am trying to find the center and radius of this circle. I thought I had it until I tried to factor it, so I appreciate any help! {{{3x^2+3y^2-6x+12y=0}}} This is what I       Log On


   

Question 70337This question is from textbook College Algebra Essentials
: Hi,
I am trying to find the center and radius of this circle. I thought I had it until I tried to factor it, so I appreciate any help!
3x%5E2%2B3y%5E2-6x%2B12y=0
This is what I have so far by completing the square...
%283x%5E2-6x%2B9%29%2B%283y%5E2%2B12y%2B36%29=0%2B9%2B36
Thank you!
note, this is Q 125 from chapter 1 Review Exercises.

This question is from textbook College Algebra Essentials

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
3x^2+3y^2-6x+12y=0
Divide thru by 3 to get:
x^2-2x+? +y^2+4y+? = 0
Complete the square on the x's and y's separately:
x^2-2x+1 + y^2+4x+4 = 1+4
Factor to get:
(x-1)^2 + (y+2)^2 = [sqrt(5)]^2
Center at (1,-2); radius=sqrt5
Cheers,
Stan H.