usually so that one can readily use the zero-product property when finding roots for a function ... used much in calculus for function analysis.
In many cases the solution in the back of the book is a factored form, and from what i understand. A factored answer is preferred, so i have just been doing it lately out of habit.
But I don't understand why this is needed in many cases. I do see that it provides a simpler answer in some cases, but in quite a few other answers the complexity of the answer is higher with the factored version.
So my question is why is it preferred?
The answers in the back are most often the work of a graduate student or a course assistant who are paid per solution. Some authors do give some guidance on how an answer should look.
I think that answers given in a textbook should be left in a form that shows the process of arriving at the answer.
One reason a factored form [b]might[b] be perferred (I would not say that it always is) is that it is typically much easier two multiply terms to get the unfactored form than it is to factor. That is, having the factored form more easily gives both forms.