5. $$x^{\frac{2}{3}} \cdot \sqrt[3]{x \cdot x}$$

$$x^{\frac{2}{3}} \cdot \sqrt[3]{x \cdot x} = x^{\frac{2}{3}} \cdot \sqrt[3]{x^2} = x^{\frac{2}{3}} \cdot x^{\frac{2}{3}} = x^{\frac{2}{3} + \frac{2}{3}} = x^{\frac{4}{3}}$$

Ответ: $$x^{\frac{4}{3}}$$