domain is all the x values...range is the y values
f(x) = 12 - 3x...f(x) is the same as y....when x = -4
y = 12 - 3(-4)
y = 12 + 12
y = 24...so when the domain (x) is -4, the range (y) = 24
f(x) = 12 - 3x....when x = -2
y = 12 - 3(-2)
y = 12 + 6
y = 18....when domain is -2, range is 18
f(x) = 12 - 3x....when x = 0
y = 12 - 3(0)
y = 12....when domain is 0, range is 12
f(x) = 12 - 3x...when x = 2
y = 12 - 3(2)
y = 12 - 6
y = 6....when domain is 2, range is 6
f(x) = 12- 3x...when x = 4
y = 12 - 3(4)
y = 12 - 12
y = 0...so when domain is 4, range is 0
so the range is (24,18,12,6,0)