Propiedades de las potencias

$\bullet9\cdot 27=3^{2}\cdot 3^{3}=3^{\left( 2+3\right) }=\boxed{3^{5}}$

$\bullet5^{10}:\left( 5\cdot 5^{7}\right) =5^{10}:5^{8}=5^{\left( 10-8\right) }=\boxed{5^{2}}$

$\bullet11^{2}.9=11^{2}\cdot 3^{2}=\left( 11\cdot 3\right) ^{2}=\boxed{33^{2}}$

$\bullet3^{2}\left( 3^{7}\right) ^{2}=3^{2}\cdot 3^{14}=3^{\left( 2+14\right) }=\boxed{3^{16}}$

$\bullet5^{9}\cdot 5^{23}:5^{11}=5^{\left( 9+23-11\right) }=\boxed{5^{21}}$

$\bullet81:2^{4}=3^{4}:2^{4}=\boxed{\left( \dfrac {3} {2}\right) ^{4}}$