Step-by-step explanation:
[tex] {7}^{ - 3} \times {7}^{ - 5} \times 7 {}^{ - 1} [/tex]
[tex] \frac{1}{7 {}^{3} } \times \frac{1}{ {7}^{5} } \times \frac{1}{7 } \\ \frac{1}{ {7}^{3 + 5 + 1 } } \\ \frac{1}{ {7}^{9} } \\ [/tex]
[tex] = {7}^{ - 3} \times {7}^{ - 5} \times {7}^{ - 1} [/tex]
[tex] = {7}^{( - 3 - 5 - 1)} [/tex]
[tex] = {7}^{ - 9} [/tex]
[tex] = \frac{1}{ {7}^{9} } [/tex]
