b=4 f(x)=1-1/x

It seems like you're working with a function \( f(x) = 1 - \frac{1}{x} \) and have a specific value \( b = 4 \). Could you please clarify what you would like to do with this function and the value of \( b \)? Here are a few possibilities:

1. Evaluate the function at \( x = 4 \): You might want to find \( f(4) \).
2. Find the inverse function: Perhaps you are interested in determining the inverse of \( f(x) \).
3. Analyze the function: You could be looking for information about its properties, such as its domain, range, or asymptotes.

Please provide more details so I can assist you accordingly!