## Precalculus (6th Edition)

$(0, 0)$; $7$ units
The circle $x^2+y^2=r^2$ has its center at $(0,0)$ and a radius of $r$ units. The given equation can be written as $x^2+y^2=7^2$. Thus, the center is at $(0, 0)$ and $r=7$. Therefore, the missing expressions in the given statement are (in order): $(0, 0)$; $7$ units