Date: Nov 13, 2013 4:27 AM
Author: Jonathan J. Crabtree
Subject: Re: Simplifying Algebraic Expressions with Subtracted Expressions

What is the story the expression describes? If the word problem involves subtraction, I suggest keeping the subtraction. If it's merely an abstract game of simplification, then you may place a superscript - before the term to denote negativity and then proceed with the usual laws.