Answer: (x + [-1], y + [1])
Explanation:
See attached. We can draw, or picture it in our heads, what the reflection would look like. Then we can pick one (or multiple to test) points and see the translation.
We can also test with a set of points. B', (2, 4) becomes G in the transformation. G is at (1, 5)
(1 - 2, 5 - 4) -> (-1, 1)