To dilate an image by a scale factor you have to mutiply the original coordinates of the point by the given factor.
For vertex O, the coordinates are (-1, -2)
Factor = 3, so multiply both coordinates by the factor:
Xcoordinate: -1*3= -3
Ycoordinate: -2*3= -6
The image of vertex O after dilating the triangle by factor 3 is (-3,-6)
