Answer:
The correct option is 1. The image of (2,4) is (4,-8).
Step-by-step explanation:
The given rule is
[tex]R_x{\circ}D_{o,2}:(2,4)[/tex]
The transformations perform from right to left. [tex]D_{o,2}[/tex] means dilation with scale factor 2 and center of dilation is origin.
The given rule defines the dilation with scale factor 2 and center of dilation is origin followed by reflection across x-axis.
If a figure dilated by scale factor k and the center of dilation is origin, then
[tex](x,y)\rightarrow (kx,ky)[/tex]
The scale factor is 2,
[tex](x,y)\rightarrow (2x,2y)[/tex]
[tex](2,4)\rightarrow (4,8)[/tex]
If a figure reflected across x-axis, then x-coordinate remains the same but the sign of y-coordinate is changed.
[tex](x,y)\rightarrow (x,-y)[/tex]
[tex](4,8)\rightarrow (4,-8)[/tex]
Therefore image of (2,4) is (4,-8) and option 1 is correct.
