а) \[ \frac{a^9 \cdot (a^3)^2}{a^{11}} = \frac{a^9 \cdot a^{3 \times 2}}{a^{11}} = \frac{a^9 \cdot a^6}{a^{11}} = \frac{a^{9+6}}{a^{11}} = \frac{a^{15}}{a^{11}} = a^{15-11} = a^4 \]
б) \[ \frac{a^3 \cdot a^8}{(a^5)^2} = \frac{a^{3+8}}{a^{5 \times 2}} = \frac{a^{11}}{a^{10}} = a^{11-10} = a^1 = a \]
в) \[ \frac{a \cdot (a^6 \cdot a^2)^5}{(a^7)^2} = \frac{a^1 \cdot (a^{6+2})^5}{a^{7 \times 2}} = \frac{a^1 \cdot (a^8)^5}{a^{14}} = \frac{a^1 \cdot a^{8 \times 5}}{a^{14}} = \frac{a^1 \cdot a^{40}}{a^{14}} = \frac{a^{1+40}}{a^{14}} = \frac{a^{41}}{a^{14}} = a^{41-14} = a^{27} \]
г) \[ \frac{(a^4 \cdot a)^12}{(a^9 : a^4)^2} = \frac{(a^{4+1})^{12}}{(a^{9-4})^2} = \frac{(a^5)^{12}}{(a^5)^2} = \frac{a^{5 \times 12}}{a^{5 \times 2}} = \frac{a^{60}}{a^{10}} = a^{60-10} = a^{50} \]
Ответ: а) a⁴; б) a; в) a²⁷; г) a⁵⁰.