a.
\(\frac{11^4\times6-11^5}{11^4-11^5}=\frac{11^4\times\left(6-11\right)}{11^4\times\left(1-11\right)}=\frac{-5}{-10}=\frac{1}{2}\)
b.
\(\frac{9^8\times3-3^{18}}{9^8\times5+9^8\times7}=\frac{9^8\times3-\left(3^2\right)^9}{9^8\times\left(5+7\right)}=\frac{9^8\times3-9^9}{9^8\times12}=\frac{9^8\times\left(3-9\right)}{9^8\times12}=-\frac{6}{12}=-\frac{1}{2}\)
c.
\(\frac{10^5-10^5\times3}{10^5\times11}=\frac{10^5\times\left(1-3\right)}{10^5\times11}=-\frac{2}{11}\)
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