Answer
$9x^{2}(4-\pi)$.
Work Step by Step
$A_{1}=s^{2}\qquad...$area of a square.
$A_{1}=(6x)^{2}\qquad...$substitute 6x for s.
$A_{1}=36x^{2}\qquad...$simplify.
$ A_{2}=\pi r^{2}\qquad$...area of a circle
$ A_{2}=\pi(3x)^{2}\qquad$...substitute 3x for r.
$A_{2}=9\pi x^{2}\qquad...$simplify.
The area of the shaded region is $A_{1}-A_{2}$, or $36x^{2}-9\pi x^{2}$.
$36x^{2}-9\pi x^{2}\qquad...$find the GCF.
$36x^{2}=2\cdot 2\cdot(3\cdot 3)\cdot(x\cdot x)$
$-9\pi x^{2}=-1\cdot(3\cdot 3)\cdot\pi\cdot(x\cdot x)$
GCF=$(3\cdot 3)\cdot(x\cdot x)$, or $9x^{2}$.
$36x^{2}-9\pi x^{2}\qquad...$factor out the GCF
$=9x^{2}(4)-9x^{2}(\pi)\qquad...$apply the Distributive Property.
$=9x^{2}(4-\pi)$
The factored form of the area of the shaded region is $9x^{2}(4-\pi)$.
