See the PurpleMath article, you need the second worked example.
CB
Oooh, I'd like to answer this as we just learned it yesterday .
To get the equation of a line passing through two points, you need to know how to work out the gradient:
or:
So to work that out with your question:
So you now have the gradient, . Now choose one of the coordinates, I'll use .
I've checked that against both of your coordinates and it works, so look over those notes and you should be able to understand it .