# How do you find the center and radius of the circle #x^2 + y^2 - 2x + 6y + 3 = 0#?

##### 1 Answer

May 23, 2016

#### Explanation:

The general equation of a circle is

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

#=sqrt(g^2+f^2-c)# the equation

#x^2+y^2-2x+6y+3=0" is in this form"# comparing like terms : 2g = -2 → g = -1 , 2f = 6 → f = 3 , c = 3

thus : centre = (1 ,-3) and r

#=sqrt((-1)^2+3^2-3)=sqrt7#