Решение:
- а) \( \frac{(x^{-7})^{-6}}{x^{-3}} = \frac{x^{(-7) \cdot (-6)}}{x^{-3}} = \frac{x^{42}}{x^{-3}} = x^{42 - (-3)} = x^{42+3} = x^{45} \)
- б) \( \frac{x^{12} \cdot x^{-15}}{x^{-7}} = \frac{x^{12+(-15)}}{x^{-7}} = \frac{x^{-3}}{x^{-7}} = x^{-3 - (-7)} = x^{-3+7} = x^4 \)
- в) \( \frac{x^{-3} \cdot x^{11}}{x^{-8}} = \frac{x^{-3+11}}{x^{-8}} = \frac{x^8}{x^{-8}} = x^{8 - (-8)} = x^{8+8} = x^{16} \)
- г) \( \frac{x^{-8} x^{13}}{x^{-7}} = \frac{x^{-8+13}}{x^{-7}} = \frac{x^5}{x^{-7}} = x^{5 - (-7)} = x^{5+7} = x^{12} \)
Ответ: а) x⁴⁵; б) x⁴; в) x¹⁶; г) x¹².