Use y=mx+b Find slope (m) using any two points. (slope = change in y over change in x) (6-0)/(12-4) = 6/8 = 3/4 Your "b" should be where the line crosses the y-axis. In this case, it tells you (0,-3) meaning it crossed the y-axis at -3. So, plugging all of these into the equation, you'd get y = (3/4)x - 3