The domain is all numbers that you can plug into x and get a real number, and range is the number you get,
since the equation is about finding the range (Y) ill change the format a little bit, it will be
Y = 8 - X , now apply the domains to the equation
# -2 as X,,,, Y = 8 -(-2) = 10 and its represented as (-2,10)
# -1 as X,,,, Y = 8 -(-1) = 9 and its represented as (-1,9)
# 2 as X,,,, Y = 8 - 2 = 6 and its represented as (2,6)
# 3 as X,,,,, Y = 8 - 3 = 5 and its represented as (3,5)
# 5 as X,,,, Y = 8 - 5 = 3 and its represented as (5,3)
i hope that was what you meant.