Hello.
Let the number be u.
Now, let's fine the product of u and -9.
We write it like this:
-9u
[tex]\bigstar[/tex] The number (in this case, it's a coefficient) is before the letter (variable)
[tex]\bigstar[/tex] We can also write it as -9*u, but we usually write it as -9u.
I hope it helps.
Have a nice day.
[tex]\boxed{imperturbability}[/tex]
