Hello!☺
[tex]Answer:\boxed{31x-9}[/tex]
[tex]Explanation:[/tex]
[tex]3x+7\times4x-9[/tex]
Let's start off by simplifying:
[tex]3x+28x+-9[/tex]
Now combine like terms:
[tex](3x+28x)+(-9)\\31x-9[/tex]
[tex]31x-9[/tex] is your answer.
Hope this helps!☺