# How do you simplify 9xy^2sqrt(400x^4y^16?

$\sqrt{400 {x}^{4} {y}^{16}} = \sqrt{{20}^{2} \cdot {\left({x}^{2}\right)}^{2} \cdot {\left({y}^{8}\right)}^{2}} = 20 {x}^{2} {y}^{8}$
$9 x {y}^{2} \sqrt{400 {x}^{4} {y}^{16}} = \left(9 x {y}^{2}\right) \cdot \left(20 {x}^{2} {y}^{8}\right)$
$= 180 {x}^{3} {y}^{10}$