Find radius and center of the equations

Thanks

2. 1)Add 16 to both sides $x^2+8x+16 + 8 + y^2= 16 \implies (x +4)^2 + y^2 = (\sqrt{8})^2$
What is the radius and center?

2)Multiply by 4 to get $x^2+y^2 = 2^2$.
What is the radius and center?

3. ## "y2" not in my question

dear "y2" not in my question..........

4. I have no idea what that means!

5. ## help

I mean y square is not in the equation