Answer:
[tex]1ab[/tex] or just [tex]ab[/tex].
Step-by-step explanation:
This is a problem where all you have to do is combine like terms.
[tex]3ab-9ab+7ab[/tex]
Subtract [tex]9ab[/tex] from [tex]3ab[/tex] first.
[tex]3ab - 9ab = -6ab[/tex]
Then, add [tex]7ab[/tex].
[tex]-6ab + 7ab = 1ab[/tex], or just [tex]ab[/tex].
