Answer:
123
Step-by-step explanation:
The given function is :
[tex]f(x)=3x^2 - 11x - 21[/tex]
We need to find the value of f(9). It can be done by putting x = 9 in the above function as follows :
[tex]f(9)=3(9)^2 - 11(9) - 21\\\\=243-99-21\\\\=123[/tex]
So, the value of f(9) is 123.
