make a table of both the points, find the difference between each x and y. For this its x=2 and y=4 so 4/2 equals 2 so you have your mx for y=mx+b. So far we have y=2x+b now we just need to find b. Since this is a linear equation all you have to do is go backwards. We have (2,8) and (4,12) so (0,4) would be b since (1,6) is just going down by the mx.
