tolong bantu jawab ya ,pakai cara :) no 15 sama 18 aja

[tex]15. \: ( \frac{1}{9} ) ^{x } = 27 \\ ( \frac{1}{9} ) ^{x} = (\frac{1}{9} ) ^{ - 3} \\ jadi \: x = - 3 \\ \\ 18. \: ( - \frac{1}{3} ) ^{ - 3} \div ( - \frac{1}{3} ) ^{ 2 } \\ (\frac{1}{3} ) ^{ - 3 - 2 } \\ ( \frac{1}{3} ) ^{ - 5} [/tex]
semoga membantu, mohon koreksinya