#### Answer

$\frac{8\sqrt {x}}{3x}$

#### Work Step by Step

$\frac{2\sqrt {16}}{\sqrt {9x}}\times\frac{\sqrt {9x}}{\sqrt {9x}}$
=$\frac{2\sqrt {16}\times\sqrt {9x}}{\sqrt {9x}\times\sqrt {9x}}$
=$\frac{2\times4\times\sqrt {9\times x}}{9x}$
=$\frac{8\times 3\sqrt {x}}{9x}$
=$\frac{8\times \sqrt {x}}{3x}$
=$\frac{8\sqrt {x}}{3x}$