One reason that negative numbers would not make sense for values of the variables is that the solution having a negative value is not valid. It might be that the expression represents a real word problem and a negative value will not make any sense. Hope this helps.
Answer:
About 113
Step-by-step explanation:
Well, there are about 453 grams in a pound.
So divide 453 by 4, and there's the answer!
453 / 4 ≈ 113