Answer:
I18 - xI such that x < 18.
ok, first let's what happens if x = 18:
I18 - xI = I18 - 18I = 0
So, at the moment we have the condition:
I18 - xI > 0.
now, if x is a really large negative number, suppose, x = -100
I18 + 100I = I118I = 118
So, as x can freely move in the negative range, we can see that I18 - xI can be any positive number, so the only restriction that we have is:
I18 - xI > 0.
This means that the domain is:
D = (-∞, 18)
and the range is:
R = (0, ∞)
