The first circle's equation is $x^{2}+y^{2}-4 x-4 y=0$, which can be rewritten as $(x-2)^{2}+(y-2)^{2}=4$. The center of this circle is at $(2,2)$ and its radius is $2$.
The second circle's equation is $x^{2}+y^{2}=16$, which is already in standard form. The
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