Explanation:
a) given slope=m1=4/b
parallel slope=m2=-8
when two lines are parallel their reltion of slopes is:
m1=m2
4/b=-8
b=-4/8
b=-1/2
b) m1=4/b , m2=3/4
when slopes are perpendicular their relation of slopes is:
m1×m2=-1
4/b × 3/4=-1
3/b=-1
b=-3
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