To determine which transformation was applied to the original pentagon with vertices at \((1,1)\), \((2,3)\), \((4,3)\), \((5,1)\), and \((3,0)\) to obtain the transformed pentagon with vertices at \((1,-1)\), \((2,-3)\), \((4,-3)\), \((5,-1)\), and \((3,0)\), we can analyze the changes in the coordinates of the vertices.
Let's compare the original vertices with the transformed vertices:
- Vertex (1, 1) transforms to \((1, -1)\)
- Vertex (2, 3) transforms to \((2, -3)\)
- Vertex (4, 3) transforms to \((4, -3)\)
- Vertex (5, 1) transforms to \((5, -1)\)
- Vertex (3, 0) stays the same at \((3, 0)\)
Notice that the y-coordinates of the first four vertices are negated (the value of y is multiplied by -1), while the x-coordinates remain unchanged for all vertices. This indicates that the transformation involved reflects the points across the x-axis.
Thus, the correct answer is:
D. reflection over the x-axis.