To evaluate $f(-6)$ for the function $f(x) = 3x - 7$, substitute $-6$ for $x$ in the function:

$f(-6) = 3(-6) - 7$

Now, calculate the expression:

$f(-6) = -18 - 7 = -25$

So, $f(-6) = -25$.

Would you like more details or have any questions about this problem?

Here are 5 related questions you might find interesting:

1. Evaluate $f(0)$ for the function $f(x) = 3x - 7$.
2. Find the value of $x$ for which $f(x) = 0$ when $f(x) = 3x - 7$.
3. Determine $f(10)$ if $f(x) = 3x - 7$.
4. What is the slope of the line represented by the function $f(x) = 3x - 7$?
5. How would you find $f(a)$ if $f(x) = 3x - 7$ for a general $a$?

Tip: To find the output of a function for a given input, substitute the input value into the function and simplify the expression.