2 points for a strate line=(1/5,4/7) & (2/5, 3/7)
deltax=2/5 -1/5=1/5
deltay=3/7 -4/7=-1/7 slope=deltay/deltax=(-1/7)/(1/5)
=(-1/7)*(5/1)=-5/7=-0.7142857 or -35.5 deg
projekt bak tu x=0...this deltax=-1/5
deltay=(-5/7)*(-1/5)=+1/7=0.1428571
y-intersept=(4/7)+(1/7)=5/7=0.7142857