Question 1044831
You can put anything you want in absolute value brackets, including negative numbers. Yes.
But the absolute value of anything cannot be a negative number.  Yes.  
|-x|=2  No problem. x=-2 and x=2.  Both of those become positive in the brackets.
|x|=-2 No.  No absolute value of anything can be negative by definition.  No matter what goes in the brackets, it cannot come out negative.