Question

Find the center of this ellipse: 9x^(2)+y^(2)+36x-4y+31=0

Answer 1

@lgbasallote or @satellite73 you know these?

Answer 2

not good with graphs sorry

Answer 3

http://www.cccg.ca/proceedings/2005/49.pdf
http://mathcentral.uregina.ca/QQ/database/QQ.09.06/s/sima1.html'
http://www.purplemath.com/modules/ellipse2.htm

Answer 4

these are the worst references ever

Answer 5

9x^(2)+y^(2)+36x-4y+31=0

or, 9 (x^2+4x +4) +(y^2-4y+4)-9=0

or, 9(x+2)^2 + (y-2)^2 = 9

or, (x+2)^2 +(y-2)^2 /9 = 1....

see that the centre is (-2,2)

Answer 6

The purplemath.com reference is exactly what you need to do this.

Answer 7

what is wrong with @bhaweshwebmasters answer?

Answer 8

do you know how to complete the square? Thats all we are doing on these.