Let's take two points:
(0, 19000) and (4.5, 8000)
So we have:
(y - yo) = m.(x - xo)
Let's sub both points
(19000 - 8000) = m.(0 - 4.5)
11000 = -4,5m
m = 11000/-4,5
m = -11000/(9/2)
m = -22000/9
So,
(y - yo) = -22000/9 .(x - xo)
Put a point:
(y - 19000) = -22000/9.(x - 0)
y - 19000 = -22000x/9
y = -22000x/9 + 19000
