We are given the function to evaluate $f(8)$ from the image. The function looks like this:

$f(8) = 2 \cdot 4(8) - 21$

Let’s break this down step by step:

1. $4 \cdot 8 = 32$
2. $2 \cdot 32 = 64$
3. $64 - 21 = 43$

Thus, the value of $f(8)$ is:

$f(8) = 43$

Would you like a detailed explanation on how to approach similar problems? Here are 5 follow-up questions:

1. What type of function is this—linear, quadratic, or something else?
2. How would the answer change if the input were $f(x) = 2 \cdot 4x - 21$ and $x = 10$?
3. Can this function have negative outputs for any value of $x$?
4. What is the y-intercept of this function if we treat it as $f(x) = 2 \cdot 4x - 21$?
5. How do transformations (shifting, stretching) affect the graph of a linear equation?

Tip: Always simplify step by step to avoid calculation mistakes.