We can use this to find the post-image vertexes
New Vertex = ( Old vertex - Dilation Center) *Scale Factor + Dilation Center
Because the Dilation Center is (0,0), this simplifies to :
New Vertex = (Old Vertex ) * Scale Factor
So we have
A' = (-4, -1)*2 = (-8, -2)
B' = (-4, -3)*2 = (-8, -6)
C' = (-1, -3)*2 = (-2, -6)