tolong dong no 7 ,8,9

[tex]7) \: \: {(2 {x}^{ - 3} {y}^{2} {z}^{ - 1})}^{3} = 8 \frac{1}{ {x}^{9} } {y}^{6} \frac{1}{ {z}^{3} } = \frac{8 {y}^{6} }{ {x}^{9} {z}^{3} } \\ 8) \: \: ( - 8 {m}^{2} {n}^{3}) \times (2 {k}^{3} {n}^{4} ) = - 16 {k}^{3} {m}^{2} {n}^{7} \\ 9) \: \: {( \frac{3 {a}^{ - 2}b }{ {c}^{4} } )}^{3} = \frac{27 {b}^{3} }{ {a}^{6} {c}^{12} } [/tex]