a) The slopes (-1 and 1) have turned over fractions (1/1 vs 1/1) and their + - signs are switched, so these lines are perpendicular.
b)
y = 0x - 5
4x - 3y = 12
-3y = -4x + 12
y = (4/3)x - 4
0 and 4/3 are different, so the lines aren't parallel.
0 and 4/3 aren't turned over fractions of each other, so the lines aren't perpendicular.
Answer: Neither.
c)
(2,2) to (4,8)
slope = (8 - 2) / (4 / 2)
slope = 6/2
slope = 3
12x - 2y = 42
-2y = -12x + 42
y = 6x - 21
The slopes (3 and 6) aren't the same, so the lines aren't parallel.
The slopes aren't fractions turned over of each other, so the lines aren't perpendicular.
Answer: Neither.