[tex] \sqrt{\frac{8x^{2}}{2x}} = \frac{\sqrt{8x^{2}}}{\sqrt{2x}} = \frac{\sqrt{4 * x^{2} * 2}}{\sqrt{2x}} = \frac{ \sqrt{4}\sqrt{x^{2}} \sqrt{2}}{\sqrt{2x}} = \frac{2x\sqrt{2}}{\sqrt{2x}} = \frac{2x}{\sqrt{x}} = 2\sqrt{x} [/tex]
The answer is D, x > 0.