me assume yu hav strate line...& 7x-4y=5 is a parallel line
& yu wanna go thru point=(8,-7)
line 1: 7x-4y=5 become 4y=7x-5 or y=(7/4)x -(5/4)
slope=7/4 or 1.75
projekt line bak from x=8 tu x=0...
deltax=-8,
deltay=deltax*slope=-8*(1.75)=-14
y=-7-14=-21....point=(0,-21)