Look at the slope. if the slopes are the same, the two lines are parallel. if the slopes are negative reciprocals, the lines are perpendicular. otherwise, neither, the two lines will intersect.
6y=x+9
y=(1/6)x+(9/6)
the slope is 1/6, while the second line has a slope of 7, so the two lines have different slopes, so choice D is correct.