Describing Reflections

To complete a glide reflection, we first perform the translation and then the reflection.

Translation

Let's begin by drawing $△ABC.$

The given rule of translation represents a vertical translation $1$ unit down. $$\begin{array}{c}(x,y)\to (x,y-1)\end{array}$$ To perform the translation, we have to subtract $1$ from each $y\text{-}$coordinate.

Reflection

To perform the reflection, we have to reflect the vertices of $△A^{\prime }{B}^{\prime }{C}^{\prime }$ to the opposite side of the $y\text{-}$axis in a way such that the distance from the vertices to the $y\text{-}$axis remains the same.

Final Glide Reflection

The final glide reflection is the combined translation and reflection.