Check below, please.
1) Let's locate the points in the figure, and then reflect across the x-axis. Note that after the reflection the points will keep the same distance from the x-axis
2) So, the pre-image is:
Pre-image Rule Image
A (3,7) (x, y)-->(x,-y) A'(3, -7)
B (6,7) B' (6,-7)
C (4,5) C' (4,-5)
D (7,5) D' (7,-5)
3) So now, let's plot the pre-image (that quadrilateral in Quadrant I) and reflect it accordingly
Note that the image is a quadrilateral reflected.