<s>[INST] sketch points given by condition on complezx number z the condition is
$|z+i| \le 3$ so its a circle with radius three centered at -i
treating $z=x+iy$
$-\sqrt{9} \le \sqrt{(x^2 )+(y+1)^2} \le \sqrt{9}$
squaring everything $-9 \le x^2 + (y+1)^2 \le 9$
$-9 \le x^2 + y^2 + 2y +1 \le 9$
I feel like I am complicating more than I need to. 
 [/INST] You're really close.
Well $|z+i|\le 3$ with $z=x+iy$ we have then simply $0\le\sqrt{x^2+(y+1)^2}\le3$ ($\forall Z\in\mathbb{C},\,|Z|\ge 0$).
Thus $x^2+(y+1)^2\le3^2$ which represents the disk of radius $3$ and center $(0,-1)$.
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