Answer
$x^2+(y +7)^2+z^2=49$
Work Step by Step
As we know the standard equation of sphere is $(x-a)^2+(y-b)^2+(z-c)^2=r^2$ ...(a)
where $(a,b,c)$ represents center and radius of the sphere is $r$
Plug $a=0,b=-7,c=0, r=7$ in equation (a).
Thus, we have $(x - 0)^2+(y -(-7))^2+(z -0)^2=(7)^2$
or, $x^2+(y +7)^2+z^2=49$
