We have a translation of 2 units to the left.
Which transformation was applied?
We can see that the original vertices are (1, 6), (−1, 3), (5, −2) and the transformed vertices are (−1, 6), (−3, 3), (3, −2)
Taking the difference between correspondent points we will get:
(-1, 6) - (1, 6) = (-2, 0)
(-3, 3)- (-1, 3) = (-2, 0)
(3, -2) - (5, -2) = (-2, 0)
So we can see that we have a translation of -2 units in the x-value, this is a translation of 2 units to the left.