strate line thru point=(12,6)
start line:...4x-3y=12, or y=(4/3)x +sumthun
its slope=4/3
but yer spozed tu make line at 90 deg tu this, so its slope=-1/slope1
slope2=-3/4
thus, y=-(3/4)x+sumthun
projekt line bak from x=12 tu x=0, so deltax=-12
deltay=slope2*deltax=(-3/4)*(-12)=+36/4=9
y=6+9=15
equashun for strate line: y=(-3/4)x+15