You can put this solution on YOUR website! The short cut answer is that the additive inverse of any number, x is -x. In this case we have
(1) x = -100
So the additive inverse is
(2) -x = -(-100) or
(3) -x = 100
Another way to find the additive inverse is to answer the question,"What number do we need to add to x in order to make the sum equal to zero." In this case
(4) x+(-x) = 0 or
(5) -100 + (-x) = or
(6) -100 + 100 = 0
So the negative inverse of -100 is +100.
Remember: The additive inverse of any number is the negative of that number.