We find this answer by multiplying the original coordinates by the scale factor 2.
The old x coordinate 9 doubles to 9*2 = 18, which is the new x coordinate.
The old y coordinate 1 doubles to 1*2 = 2, which is the new y coordinate.
The dilation rule can be stated as [tex](x,y) \to (2x,2y)[/tex], which means [tex](9,1) \to (18,2)[/tex]