Applying a dilation centered at the origin with scale factor [tex]k[/tex] has the effect of multiplying both coordinates of a point by [tex]k[/tex]:
[tex](x,y)\mapsto (kx,ky)[/tex]
So, in your case, the coordinates of the points double:
[tex]J'=(4,8),\quad K'=(8,8),\quad P'=(6,4)[/tex]
