9) x¹⁷.(x¹²)³ x¹⁵

$$\frac{x^{17} \cdot (x^{12})^3}{x^{15}} = \frac{x^{17} \cdot x^{12 \cdot 3}}{x^{15}} = \frac{x^{17} \cdot x^{36}}{x^{15}} = \frac{x^{17+36}}{x^{15}} = \frac{x^{53}}{x^{15}} = x^{53-15} = x^{38}$$

Ответ: x³⁸