Simplify plus or minus square root of 121x^4y^16

$\pm \sqrt{121 x^{4} y^{16}}$

Rewrite $121 x^{4} y^{16}$ as ${(11 x^{2} y^{8})}^{2}$ .

$\pm \sqrt{{(11 x^{2} y^{8})}^{2}}$