Find coordinates of points in space, after a reflection around x axis
First find distance from points of parallellogram to x axis
In this case all are negative points, then theyre turned positive in y coordinates ( x coordinate remains equal).
Reflection means similar figure but drawed at opposed distance from x axis.
Then
R (3,-9) becomes. R' (3,9)
S (3,-5) turns to S' (3, 5)
T (4,-4) becomes T' (4,4)
U (4,-8) turns to U' (4,8)