Answer
$x^2+y^2 \leq 9$
This is the region inside the circle $x^2+y^2=9$
Work Step by Step
We have $\iint_{R} (x^2+y^2-9) dA$
The integral must be minimum on the region when $x^2+y^2-9 \leq 0$
So, $x^2+y^2 \leq 9$
This is the region inside the circle $x^2+y^2=9$
