The expression you provided for $f(1)$ is $f(1) = 2(-1)$.

Let's calculate:

$f(1) = 2(-1) = -2$

So, $f(1) = -2$.

Would you like any further details or have any questions?

Here are 5 related questions to expand on this concept:

1. What is the general form of the function $f(x)$ if $f(1) = -2$?
2. How would you calculate $f(x)$ for other values of $x$?
3. What would $f(-1)$ equal if the same function rule applied?
4. How do we determine if this function is linear or not?
5. What is the graphical representation of this function?

Tip: Always simplify expressions inside the function before evaluating the result.