Answer:
[tex]\huge \boxed{7x+9}[/tex]
Step-by-step explanation:
[tex]3x + 4x + 8 - (-1)[/tex]
Distributing the negative sign to the term in the brackets.
[tex]3x + 4x + 8 +1[/tex]
Combining like terms.
[tex]7x+9[/tex]