Answer:
[tex]\large \boxed{\sf \ \ -3x^3-x^2+x+18 \ \ }[/tex]
Step-by-step explanation:
Hello, please consider the following.
[tex](f-g)(x)=f(x)-g(x)=x^2-3x+9-(3x^3+2x^2-4x-9)\\\\=x^2-3x+9-3x^3-2x^2+4x+9\\\\=\boxed{-3x^3-x^2+x+18}[/tex]
Hope this helps.
Do not hesitate if you need further explanation.
Thank you
