Functions given:
[tex]f\mleft(x\mright)=3x+9[/tex][tex]g\mleft(x\mright)=5-2x[/tex]The task given can be also displayed as follows:
[tex]\mleft(f+g\mright)\mleft(x\mright)=f\mleft(x\mright)+g\mleft(x\mright)[/tex]Meaning that (f+g)(x) is the addition of both functions.
[tex]\mleft(f+g\mright)\mleft(x\mright)=f(x)+g\mleft(x\mright)=(3x+9)+(5-2x)[/tex]Simplifying we get:
[tex]=3x+9+5-2x[/tex][tex]=x+14[/tex]Answer: B. x + 14
