Answer
(a) $(1,2)$, $3$. (b) see graph. (c) $(1\pm\sqrt 5,0)$, $(0,2\pm2\sqrt 2)$
Work Step by Step
(a) Given $x^2+y^2-2x-4y-4=0$, form squares to get $(x-1)^2+(y-2)^2=9$. We can identify its center $(h,k)=(1,2)$ and radius $r=3$.
(b) see graph.
(c) To find the x-intercepts, letting $y=0$, we have $x^2-2x-4=0$ which gives $(1\pm\sqrt 5,0)$. To find the y-intercepts, letting $x=0$, we have $ y^2 -4y-4=0$ which gives $(0,2\pm2\sqrt 2)$
