Answer
In order to get A'B'C'D'E', you would reflect ABCDE across the Y axis at X = 5.
Explanation:
The easiest to explain this is you are essentially placing the Y axis at X = 5. In this case, we are setting a vertical line at (5, ∞) , and you can reflect your figure across that from it's current position.
In the first picture, you can see the two figures, and the new line at X = 5.
The second picture shows how the figure is reflected and mapped onto A'B'C'D'E'.
If you need a general overview of how to do reflections or just want to watch a neat video, I have one on my channel, Simpl Algebra