How do you find the center and radius of the circle given #x^2+y^2+2x-10=0#?

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Answer 1 · 2018-03-31T10:41:00

centre #C (-1,0) and r=sqrt11#

The general equation of the circle:

#x^2+y^2+2gx+2fy+c=0.......to(I)#,

whose centre #C(-g,-f) and # radius #r=sqrt(g^2+f^2-c)#

We have,

#x^2+y^2+2x-10=0#

Comparing with #(I)#, we get

#2g=2,2f=0,c=-10#

i.e. #g=1,f=0,c=-10#

So,

centre #C(-1,0) and r=sqrt((1)^2+(0)^2-(-10))=sqrt11#