For 1a the lines are Parallel because 12x=3y+7 is 3y=12x-7. 3/3 is 1 and 12/3 is 4 so 1y=4x-7. So on the first line you start at -1 and on the second -7, and the slope is the same, so the lines would go up at the same rate making them parallel because they started in different y coordinates.