D stands for dilatation. the sub (0) = center and the sub (3) represents the scale factor. The scale factor "k" being 3, means the actual image has been dilated 3 times versus the pre-image or reciprocally, the pre-image is a reduction of the image by a factor k₁= 1/3
The coordinate of A' in the image A(-3, 6) The coordinate of A in the pre-image should be A(-3.k₁, 6k₁)
But k₁ =1/3, then A(-3/3 , 6/3) = A(-1 , 2) (Second Answer)
