It seems like the most relevant information to answer the question about the function f(x)=-1/3 x +4 is that it is a linear function and that its value can be calculated by plugging in the given value for x. Specifically, to calculate the value of f(-9), we can simply substitute -9 for x in the equation and evaluate:
f(-9) = (-1/3)(-9) + 4 = 7