Question

If 5-5=0, then does (-5)-5=0? And does that mean that (-5)-(-5)=0?

Answer 1

(-5)-5 = -10
(-5)-(-5) = -5+5 = 0

Answer 2

I think you intended to type:
|-5| - 5 = 0

|-5| means the absolute value of -5 which is its distance from zero.
That distance is 5 for +5 and it is 5 for -5
(If you do physics, |5| is magnitude and -5 includes direction so is a vector. |-5| = |+5| = 5, the magnitude
but -5 is opposite in direction from +5 )

In other words |-5| is just 5
and if you take 5 from 5 you get 0