Question Number 47071 by 23kpratik last updated on 04/Nov/18
$${prove}\:{that}\:{union}\:{of}\:{two}\:{subgroups}\:{of}\:{a}\:{group}\:{is}\:{a}\:{subgroup}\:{iff}\:{one}\:{is}\:{contained}\:{in}\:{other} \\ $$
prove-that-union-of-two-subgroups-of-a-group-is-a-subgroup-iff-one-is-contained-in-other-