The given function is:

$f(x) = -6.66 + 1.64|x|$

To find $f(-3)$, substitute $x = -3$ into the function:

$f(-3) = -6.66 + 1.64| -3 |$

Since the absolute value of $-3$ is 3:

$f(-3) = -6.66 + 1.64 \times 3$

Now, perform the multiplication:

$f(-3) = -6.66 + 4.92$

Finally, add the values:

$f(-3) = -1.74$

So, $f(-3) = -1.74$.

Would you like further clarification on the steps or the function?

Here are some related questions you might find interesting:

1. How do absolute values impact the outcome in a function?
2. What would happen if the coefficient of $|x|$ were negative?
3. Can you find $f(0)$ for this function?
4. How would the graph of this function look based on the rule?
5. What are the real-world applications of functions with absolute value?

Tip: When dealing with absolute value in functions, remember that $|x|$ always makes $x$ non-negative, so it helps ensure the function stays well-behaved across positive and negative inputs.