Решение:
- \(\frac{(x^{-7})^{-6}}{x^{-3}} = \frac{x^{(-7) \cdot (-6)}}{x^{-3}} = \frac{x^{42}}{x^{-3}} = x^{42 - (-3)} = x^{42+3} = x^{45}\)
- \(\frac{x^{12} \cdot x^{-15}}{x^{-7} \cdot x^{11}} = \frac{x^{12+(-15)}}{x^{-7+11}} = \frac{x^{-3}}{x^4} = x^{-3-4} = x^{-7}\)
- \(\frac{x^{-8}}{x^{-7} \cdot x^{-8}x^{13}} = \frac{x^{-8}}{x^{-7+(-8)+13}} = \frac{x^{-8}}{x^{-15+13}} = \frac{x^{-8}}{x^{-2}} = x^{-8-(-2)} = x^{-8+2} = x^{-6}\)
Ответ: а) \(x^{45}\); б) \(x^{-7}\); в) \(x^{-6}\).