Your answer would be −5 and 5/18
You turn the mixed fractions into improper fractions. So for 2 and 1/6 you get 13/6, and -4 and 7/9 would be -29/9.
Then find the LCM of those fractions and that number would be 18. So 13/6+(-8/3)+(-29/9) will all have a denominator of 18.
Then you add them up and you will get a improper fraction which would be -67/18
Your Final answer will be -5 and 5/18
Sorry for the longness I didn't know if you wanted it explained