Answer:
F(x) = -3^(27)
According to the way the question was arranged, the answer above is the answer.
But the options given none of them matches my answer.
Step-by-step explanation:
A function is defined as (f of x)
= -3^4√x-9.
F(x)= -3^(4√x-9) at x= 81
√x= √81
√x= 9
F(x)= -3^(4(9)-9)
F(x) = -3^(36-9)
F(x) = -3^(27)
