Let's solve for $f(-7)$.

The function given is: $f(-7) = 5 - \frac{3}{7}(-7)$

First, simplify the fraction: $\frac{3}{7}(-7) = -3$

Now substitute this into the equation: $f(-7) = 5 - (-3)$

Simplify the expression: $f(-7) = 5 + 3 = 8$

So, $f(-7) = 8$.

Would you like more details or have any questions?

Here are 5 related questions to practice:

1. What is $f(7)$ if $f(x) = 5 - \frac{3}{7}x$?
2. How would the function change if the coefficient of $x$ was $\frac{4}{7}$ instead?
3. What is the slope of the function $f(x) = 5 - \frac{3}{7}x$?
4. What happens to the value of $f(x)$ as $x \to \infty$?
5. How would you write the equation $f(x) = 5 - \frac{3}{7}x$ in slope-intercept form?

Tip: When dealing with fractions and negative numbers, simplify carefully by treating each operation step by step to avoid errors.