garis 3y = x + 1 dan titik ( -3,4)

3y = x + 1
  y = (1/3)x + 1/3
m = 1/3
Persamaan garis:
y - b = m(x - a)
y - 4 = (1/3)(x + 3)
3y - 12 = x + 3
x - 3y + 15 = 0

3y=x+1
y=1/3x+1/3

y-y1=m(x-x1)
y-4=1/3(x+3)
y=1/3x+3/3+4
y=1/3x+1+4
y=1/3x+5
---------------kalikan 3
3y=x+15
x-3y+15=0