Answer:
[tex] \boxed{ \bold{ \huge{ \boxed{ \sf{ {8u}^{18}}}}}} [/tex]
Step-by-step explanation:
Using the power to power law of indices
i.e When an algebraic term in the index form is raised to another index , the base is raised to the product of two indices.
Now, Let's simplify
[tex] \star \: \sf{({8u}^{9})^{2} }[/tex]
[tex] \dashrightarrow{ \sf{(8 {u})^{9 \times 2}}} [/tex]
[tex] \dashrightarrow{ \boxed{ \sf{ {8u}^{18}}}} [/tex]
Hope I helped!
Best regards! :D