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Choose a simple preimage and reflect it across the line y=5. What can we say about the values of the obtained reflection?
No, see solution.
We are told that Jorge said that the y-values of a preimage would stay the same after reflecting it across the line y=5, since y-values stay the same when we reflect a preimage across the y-axis. We want to determine if he is correct. To do so, let's pick a simple preimage — for example a triangle — and reflect it across the line y=5.
Finally, we can connect the reflected points in order to obtain the reflection of our preimage.
Note that it is the x-values of the preimage that did not change. The y-values changed, because the reflection across the line y=5 moved them to the other side of this line. Therefore, Jorge is wrong. However, if we reflect a preimage across the y-axis the y-values do not change, because this axis is vertical, not horizontal.
