A dilation of a point by a factor of 4 means that its coordinates will be multiplied by 4, so the image of the point (x,y) after the dilation will be (4x,4y). With this in mind, let's solve the problem:
[tex]H\text{ = }(12\cdot4,-8\cdot4)=(48,-32)[/tex]The answer is (48,-32).