In order to get the answer to this question you will have to use KCC (Keep, Change, Change) and then solve.
[tex]-1.8 - 3.9=[/tex]
Using KCC:
[tex]-1.8-3.9=-1.8+-3.9[/tex]
[tex]-1.8 + -3.9 = -5.7[/tex]
[tex]= -5.7[/tex]
Therefore your answer is option D "-5.7."
Hope this helps.
