paralell has same slope
or
for
ax+by=c
an equation with same slope is
dx+ey=f where d=a and b=e
so
x-3y=c
find c
(6,1)
(x,y)
x=6
y=1
6-3(1)=c
6-3=c
3=c
x-3y=3
slop eintercept
solve fo ry
add 3y to both sides
x=3y+3
minus 3 both sides
3y=x-3
divide both sidse by 3
y=1/3x-1