the equation of a line parallel to the given line... thats easy
In the equation, -4 is the angle of the line, and 6 is how far up/down the line is offset from the origin (center point). Any parallel line would have the same angle. Putting any number in for the 6 would produce a parallel line.
Examples:
y=-4x+7
y=-4x+8
y=-4x+9
y=-4x+10
et cetera....
all of those are parallel.