\[\boxed{\text{277\ (277).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ 8x^{6} = 2^{3} \cdot \left( x^{2} \right)^{3} = \left( 2x^{2} \right)^{3}\]
\[2) - 27x^{3}y^{9} =\]
\[= ( - 3)^{3} \cdot x^{3} \cdot \left( y^{3} \right)^{3} = \left( - 3{xy}^{3} \right)^{3}\]
\[3)\ 0,001x^{12}y^{18} =\]
\[= (0,1)^{3} \cdot \left( x^{4} \right)^{3} \cdot \left( y^{6} \right)^{3} =\]
\[= \left( 0,1x^{4}y^{6} \right)^{3}\]
\[4) - \frac{125}{216}x^{15}y^{21}z^{24} =\]
\[= \left( - \frac{5}{6} \right)^{3} \cdot \left( x^{5} \right)^{3} \cdot \left( y^{7} \right)^{3} \cdot \left( z^{8} \right)^{3} =\]
\[= \left( - \frac{5}{6}x^{5}y^{7}z^{8} \right)^{3}\]