perpendikular bisekter av line tween points (1,5) & (8,13)
start line...deltax=7, deltay=8
slope=deltay/deltax=8/7
y1=(8/7)x +konst1
projekt line tu x=0...deltax=-1, deltay=slope*deltax=-8/7
y1-intersept=5-(8/7)
midpoint...x=9/2, y=9 or (4.5,9)
######## perp line hav slope=+7/8 & go thru point=(4.5,9)
y2=(7/8)x+konst2
projekt line tu x=0...deltax=-4.5
deltay=slope*deltax=(7/8)*(-4.5)=-3.9375
konst2=9-3.9375=5.0625
y2=(7/8)x+5.0625