Let's make this simple. Since we are given a ratio, that is the method we will use (as opposed to being told that the coordinate of the point that partitions the directed segment is one-third of the way from the first point to the second point. That's a different method). There is a formula for each of the coordinates we are looking for and they are:
and where
a = 4 (from the ratio),
b = 3 (from the ratio),
x1 = 1, y1 = -6,
x2 = 8, y2 = 8 (those are from the endpoints of the directed segment). Filling in to find x first:
Since you can plug the first 2 coordinates into the slope equation () you will get 4 for the slope so for the equation for the parallel line you would get y=4x+4 and since the x=4 you could plug that in and you would get y=20 and x=4