I tried to do this on my own and I got nine and they said it was incorrect so please help

Answer:
9u
Explanation:
Given the expression:
[tex]3u(3)[/tex]First, replace the parenthesis with a multiplication sign.
[tex]\begin{gathered} =3u\times3 \\ =3\times u\times3 \end{gathered}[/tex]Next, reorder to bring the numbers together.
[tex]\begin{gathered} =3\times3\times u \\ =9u \end{gathered}[/tex]The simplified form of the expression is 9u.