i need help please , answer ASAP if you know the answer

Answer: 9
Step-by-step explanation:
The problem is asking for the value of f(x) when x=6. All you have to do is plug in 6 into every x you see and then solve.
[tex]f(6)=\frac{6^2}{2} -9[/tex]
[tex]f(6)=\frac{36}{2} -9[/tex]
[tex]f(6)=18-9[/tex]
[tex]f(6)=9[/tex]