want strate line 90 deg tu line4.....y=(5/7)x+konst
refer line hav slope=5/7, so want slope=-(7/5) tu be 90 deg from that thang
y=(-7/5)x + konst
this line go thru point=(-5,4)
projekt line from x=-5 tu x=0...deltax=+5
deltay=slope*deltax=(-7/5)*5=-7
y=4-7=-3
point=(0,-3)
y=-(7/5)x-3