|120-x| if x<120

Question

|x-120| if x<120

Answer 1

recall that
|n| = n if n≥0
|n| = -n if n < 0

so, that means that
if x < 120, 120-x > 0
so |120-x| = 120-x if x < 120
and so, of course,
|x-120| = -(x-120) = 120-x if x < 120