The above question is pretty simple, and I used common sense to figure out that the coordinates (3, -7) is the answer, since it is the only viable spot.
I was wondering how I would find the scale factor used to dilate figure ABCD. I tried using image/pre-image. That didn't work, because I was getting different results for different coordinates. I'd like to know a method on finding the scale factor.
I think you simply need to compute the ratio between the length of the segment $AD$ and the length of the corresponding segment $JM$, in this case: $$\frac{\sqrt{(-4-(-2))^2+(-7-(-3))^2}}{\sqrt{1^2+2^2}}=\sqrt{\frac{20}{5}}=\sqrt{4}=2.$$