Answer
(a). $(h,k)=(-2,0), r=2$.
(b). See graph.
(c). $(-4,0),(0,0)$
Work Step by Step
(a). $x^2+4x+y^2=0\longrightarrow (x+2)^2+(y)^2=4$, thus $(h,k)=(-2,0), r=2$.
(b). See graph.
(c). For x-intercept(s), let $y=0$, we get $(-2\pm2,0)$ or $(-4,0),(0,0)$, for y-intercept(s), let $x=0$, we get $(0,0)$.
