Find the relative rate of change of $f(x)$ at the indicated value of $x$.
\[
f(x)=282-3 x ; x=22
\]
The relative rate of change of $f(x)$ at $x=22$ is
(Type an integer or decimal rounded to three decimal places as needed.)

Step 1 ：Given the function \(f(x) = 282 - 3x\), we first need to find the derivative of the function.

Step 2 ：The derivative of \(f(x)\) is \(-3\).

Step 3 ：Substitute \(x = 22\) into the derivative, we get \(-3\).

Step 4 ：Substitute \(x = 22\) into the original function, we get \(216\).

Step 5 ：The relative rate of change of a function at a certain point is given by the derivative of the function at that point divided by the function value at that point. So, the relative rate of change of \(f(x)\) at \(x=22\) is \(-3/216 = -1/72\).

Step 6 ：Final Answer: The relative rate of change of \(f(x)\) at \(x=22\) is \(\boxed{-0.014}\).