# How do you graph #x^2+y^2+3x-6y+9=0#?

##### 1 Answer

Mar 5, 2016

circle : centre

#### Explanation:

The general form of the equation of a circle is :

# x^2 + y^2 + 2gx + 2fy + c = 0 # centre = (-g,-f) and r =

#sqrt(g^2+f^2 - c )#

#x^2 + y^2 + 3x - 6y + 9 = 0 " is in this form "# and by comparison : 2g = 3 → g

#=3/2# , 2f = -6 → f = -3, c=9centre =

#(-3/2 ,3 )" and " r = sqrt((3/2)^2+(-3)^2-9)=3/2#