Question 1005790

 
if the center is ({{{h}}},{{{k}}})=({{{-1}}},{{{-4}}}) and a point on the circle is ({{{x}}},{{{y}}})=({{{-1}}},{{{1}}}) we will use it to find the radius {{{r}}}

{{{(x-h)^2+(y-k)^2=r^2}}}

{{{(-1-(-1))^2+(1-(-4))^2=r^2}}}

{{{(-1+1)^2+(1+4)^2=r^2}}}

{{{(0)^2+(5)^2=r^2}}}

{{{25=r^2}}}

{{{r=5}}}


{{{(x+1)^2+(y+4)^2=5^2}}}

{{{(x^2+2x+1)+(y^2+8y+16)=25}}}

{{{x^2+2x+1+y^2+8y+16-25=0}}}

{{{x^2+y^2+2x+8y+17-25=0}}}

{{{x^2+y^2+2x+8y-8=0}}}