(i)

x = 11/15

The additive inverse of x = 11/15 is -x = 11/15 as 11/15 + ( - 11/15 ) = 0

This equality 11/15 + ( - 11/15 ) = 0 represents that the additive inverse of - 11/15 is 11/15 or it can be said that - ( - 11/15 ) = 11/15 i.e, -(-x) = x

(ii)

x = -13/17

The additive inverse of x = -13/17 is -x = 13/17 as -13/17 + 13/17 = 0

This equality -13/17 + 13/17 = 0 represents that the additive inverse of 13/17 is -13/17 i.e, -(-x) = x