Determine which of the lines are parallel and which of the lines are perpendicular.

Line a passes through (-3, 1) and (1, 7).
Line b passes through (2, 3) and (8, 0).
passes through (-1, –9) and (5, 3).
- 6) and (-6, 1).
Line
Line d passes through (8,-6) and (-6,1)