23. S is a set of integers such that
I) If x is in S, then -x is in S.
II) If both x and y are in S, then so is x + y.
Is -2 in S?
(1) 1 is in S.
(2) 0 is in S.
I) If x is in S, then -x is in S.
II) If both x and y are in S, then so is x + y.
Is -2 in S?
(1) 1 is in S.
(2) 0 is in S.
