Question: The graph of $y = f(x)$ is shown below (dashed curve). Reposition the two green draggable points to obtain the graph of $y = -f(x - 4) + 1$ (solid curve).
1. **State the problem:** We are given the graph of $y = f(x)$ and need to find the graph of $y = -f(x - 4) + 1$ by repositioning points.
2. **Understand the transformation:** The function $y = -f(x - 4) + 1$ involves three transformations:
- Horizontal shift right by 4 units (due to $x - 4$ inside the function).
- Reflection about the x-axis (due to the negative sign in front of $f$).
- Vertical shift up by 1 unit (due to $+1$ outside the function).
3. **Apply horizontal shift:** For any point $(x, y)$ on $y = f(x)$, the corresponding point on $y = f(x - 4)$ is $(x + 4, y)$.
4. **Apply reflection:** Reflect the $y$-value about the x-axis: $y$ becomes $-y$.
5. **Apply vertical shift:** Add 1 to the $y$-value: $-y + 1$.
6. **Combine steps:** For a point $(x, y)$ on $y = f(x)$, the transformed point on $y = -f(x - 4) + 1$ is:
$$ (x + 4, -y + 1) $$
7. **Example with key points:**
- If a key point on $f$ is at $(0, 0)$, then on the transformed graph it is at:
$$ (0 + 4, -0 + 1) = (4, 1) $$
- If another key point is at $(2, 4)$, then on the transformed graph it is at:
$$ (2 + 4, -4 + 1) = (6, -3) $$
8. **Conclusion:** To reposition the green draggable points, move each point from $(x, y)$ to $(x + 4, -y + 1)$ to obtain the graph of $y = -f(x - 4) + 1$.