Answer:
(-1, 1), (-1, 2), (0, 1)
Step-by-step explanation:
It appears as though letter designations have become confused. If not, your question answers itself, as a, b, c are given and you're asking for a, b, and c.
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Reflecting the given points across the line y=-x transforms them like this:
(x, y) ⇒ (-y, -x)
That is, you swap the coordinates and negate them both. The result will be as shown above and in the attachment.