What is the additive inverse of 18xy?

It is the opposite of the given number.

Answer = -18xy.

The additive inverse of a number is the number that, when added to the original number, equals zero. To find the additive inverse of a term, we need to change the sign of the term and keep the same coefficient.

In this case, the term is 18xy. To find its additive inverse, we need to change the sign and keep the coefficient the same. So, the additive inverse of 18xy would be -18xy.