Answer:
7^-9×÷7^9
7^-18 this one may help you
[tex] {7}^{ - 9} \div {7}^{9} [/tex]
[tex] {7}^{ - 9 - 9} [/tex]
[tex] {7}^{ - 18} \: ans[/tex]
if it is simple divide then
[tex] \frac{1}{ {7}^{18} } \: ans[/tex]
