Hello from MrBillDoesMath!
Answer:
Sometimes!
Discussion:
Consider these examples:
abs(3) = 3 ( so abs(x) = x for this value of x)
abs(-3) = 3 ( so abs(x) <> x for this value of x)
In general,
if x >= 0, then abs(x) = x
if x < 0, then abs(x) = -x
Thank you,
MrB