me assume yer ramblings tri tu impli yu hav a strate line tween 2 points... 2 points=(0,4) & (5, -8)... Then yu impli point 2=midpoint av a line yu wanna find... deltax=5, deltay =-12... tu extend line same distans, add same numbers tu point 2... thus, point 3=(5+5, -8-12)=10, -20)