Question

The number k and 1.4 are additive inverses.

Answer 1

For this case we have the following definition:
 The additive inverse of a number is the opposite of that number, that is, the additive inverse of a number x is - x. The sum of a number and its additive inverse is equal to zero.
 We have then: 
 $1.4 + k = 0$
 From here, we clear the value of k.
 $k = -1.4$
 Then, we place the values on the number line.
 Answer:
 See attached image.