You have to look at the slope... if the slope is the same the lines are parallel.
If the slope is the negative reciprical they are perpendicular. 4 the negative reciprical is -1/4.
The concurrent lines have a point they all go through.
a). y=3x+3
b). y=3x-2
c). y=2x+4
d). 2y=4x+4
e). y=2/3x+3
f). y=-3/2x+3
g). 4x+3y=6
h). 4x+3y=8
a) and b), c) and d) and g) and h) are parallel.
e) and f) are perpendicular.
g) and h) are the same line.