When you subtract a negative with a negative does it equal a positive or a negative

Complete the equation of the line through (−10,3) and (−8,−8). use exact numbers.

The function f(x) = 14,600(1.1)* represents the population of a town x years after it was established. what was the original population of the town?

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible