Ответ:
- \(\frac{a^{11}\times a^6}{a^{15}}=a^{11+6-15}=a^2\).
- \(\frac{(a^7)^3\times a^5}{a^{20}}=a^{21+5-20}=a^6\).
- \(\left(\frac{a^4}{b^2}\right)^2:\left(\frac{a^5}{(b^2)^3}\right)^2=\frac{a^8}{b^4}:\frac{a^{10}}{b^{12}}=\frac{a^8}{b^4}\cdot\frac{b^{12}}{a^{10}}=\frac{b^8}{a^2}\).
Ответ: 1) \(a^2\); 2) \(a^6\); 3) \(\frac{b^8}{a^2}\).
