The image contains a mathematical problem that reads:

"Persamaan garis $f(x) = 3x + 4$ didiferensiasi terhadap garis $y = -4$. Tentukan nilai $f'(3)$!"

This is asking for the derivative of the linear function $f(x) = 3x + 4$ and to evaluate that derivative at $x = 3$.

Solution:

1. The function given is $f(x) = 3x + 4$.
2. To differentiate this function with respect to $x$, we use the basic rule of differentiation for polynomials: $f'(x) = \frac{d}{dx}(3x + 4)$ The derivative of $3x$ is 3 (since the derivative of $x^n$ is $nx^{n-1}$, and here $n = 1$), and the derivative of the constant $4$ is 0. Therefore: $f'(x) = 3$
3. Now, we evaluate $f'(3)$: $f'(3) = 3$

Thus, the value of $f'(3)$ is 3.

Do you need further clarification or have any additional questions?

Here are some related questions that expand on this topic:

1. What is the geometric interpretation of the derivative of a function?
2. How do you differentiate more complex functions, such as products or quotients of functions?
3. What is the physical meaning of the derivative in real-world problems?
4. How does the concept of the slope of a line relate to the derivative?
5. How would you find the second derivative of the given function $f(x) = 3x + 4$?

Tip: For linear functions like $f(x) = ax + b$, the derivative is always the slope $a$, because the rate of change is constant.