please help will vote brainliest

Answer:
D
Step-by-step explanation:
Start by factoring out each radical.
[tex]\sqrt{16x^{3}} = \sqrt{16}*\sqrt{x^{3}} = 4\sqrt{x^{3}}[/tex]
[tex]\sqrt{8x} = \sqrt{4} * \sqrt{2x} = 2\sqrt{2x}[/tex]
Add them to get:
[tex]\frac{4\sqrt{x^{3}}}{2\sqrt{2x}} = \frac{4\sqrt{x}\sqrt{x}\sqrt{x}}{2\sqrt{2}\sqrt{x}} = \frac{4\sqrt{x}\sqrt{x}}{2\sqrt{2}} = \frac{2x^{2}}{\sqrt{2}} = \sqrt{2} x^{2}[/tex]
D is the answer