5. a) False, 4 is a member of
this set but {4} is not.
b) True, there are 23
subsets of this set: {1},{{3}}, {4}, {1,{3}}, {1,4}, {{3},4}, {1,{3},4} and the empty set.
c) True, {3} is a member of this set.
d) False, 1 is a member of this set,
but the subset containing 1 is {1}.