Explanation:
(m1) slope of L1=-(2-k)/-1=2-k
(m2) slope of L2=-8/k
a)
if they are parallel
m1=m2
2-k=-8/k
2k-k²=-8
k²-2k-8=0
k²-4k+2k-8=0
k(k-4)+2(k-4)=0
(k-4)(k+2)=0
either
k=4
or
k=-2
when lines are perpendicular
m1m2=-1
(2-k)×-8/k=-1
-16+8k=-k
8k+k=16
9k=16
k=16/9
