Question: b) Reflect the letter $Y$ in the vertical line. Do this in red. Now reflect it in the horizontal line, in green.
1. **Problem Statement:**
Reflect the letter $Y$ first across the vertical line (y-axis) and then across the horizontal line (x-axis).
2. **Reflection Rules:**
- Reflection across the vertical line (y-axis) changes the $x$-coordinate of each point to its opposite, i.e., $(x,y) \to (-x,y)$.
- Reflection across the horizontal line (x-axis) changes the $y$-coordinate of each point to its opposite, i.e., $(x,y) \to (x,-y)$.
3. **Step 1: Reflect $Y$ across the vertical line (y-axis):**
- For each point $(x,y)$ on the $Y$, the reflected point is $(-x,y)$.
- This reflection is drawn in red.
4. **Step 2: Reflect $Y$ across the horizontal line (x-axis):**
- For each point $(x,y)$ on the $Y$, the reflected point is $(x,-y)$.
- This reflection is drawn in green.
5. **Summary:**
- The original $Y$ is above the x-axis and slightly left of the y-axis.
- The red reflected $Y$ is the mirror image across the vertical line.
- The green reflected $Y$ is the mirror image across the horizontal line.
This completes the reflections as requested.