28. -28/-4=+7 because in devision a negative denominator and dominator is positive.
29.-10/2=-5 this is because a negative number dividing a positive number is negative.
30. 12/-6=-2 because a positive dividing a negative number is also negative
31. -54/6 =-9 because a negative dividing a positive number is given as negative also
I hope this answer could help