Question

In limits topic I came across a definition as |f|(x) = | f(x) |?

I know what the lateral means, but what is meant by the left hand size?

Answer 1

never seen it, but maybe it's akin to
(f◦g)(x) = f(g(x))

looks like you have some reading to do.

Answer 2

I can post a picture of the lecture note but this site doesn't allow this feature. It's hard to show it