Sort:  

@dkmathstats, yes but the questions says If X is a negative integer. 0 is a special number.

Zero is neither negative nor positive.

There may be confusion in the third question.

I'm viewing the third question as the first one from the above. Given x as a negative, the sum is negative.

Coin Marketplace

STEEM 0.21
TRX 0.26
JST 0.040
BTC 101165.24
ETH 3668.48
USDT 1.00
SBD 3.16