-7 + 56x = 105
56x = 105 + 7
56x = 112
x = 2
-4.2 degrees. What you would do is from 8-12 (midnight) is 4 hours. So it dropped -16.8 degrees in those 4 hours so -16.8 / 4 is -4.2 degrees. So it dropped -4.2 degrees every hour but it was also -4.2 degrees at 9:00 p.m.
-50 because if he owes 10 different people the same amount it would be -50 because he owes them money