the domain is basically the x value and range is the y value in (x, y). so in this, they are giving you the domain so just plug in the domain numbers into the equation to find the answer.
k = {(x, y)|x - y = 5}
(0, y) (0, -5)
0 - y = 5
y = -5
(2, y) (2, -3)
2 - y = 5
-y = 5 -2
-y = 3
y = -3
(4, y) (4, -1)
4 - y = 5
-y = 5 - 4
-y = 1
y = -1
hope this helped, God bless!
