#### Answer

Center is $(-2,0,2 )$ and radius is $\sqrt 8$

#### Work Step by Step

As we know the standard equation of sphere is $(x-a)^2+(y-b)^2+(z-c)^2=r^2$
where $(a,b,c)$ represents center and radius of the sphere is $r$
$x^2+y^2+z^2+4x-4z=0 \implies x^2+4x+y^2+z^2-4z=0$
$ \implies (x - 2)^2+y^2+(z - 2)^2=8$
and $(x -(- 2))^2+y^2+(z - 2)^2=(\sqrt 8)^2$
Thus, we have Center is $(-2,0,2 )$ and radius is $\sqrt 8$