We are given the segment RQ and the mapped (transformed) segment R'Q'.
It's evident the coordinates of R and R' are the result of a reflection across the x-axis. Point (3, 2) mapped to (3, -2).
The same occurs with point Q(4, 5) that mapped to Q'(4, -5). The rule is a reflection across the x-axis.
Thus, the rule is "Reflection across the x-axis" that maps (x, y) to (x, -y)
