Charles's Responses in WyzAnt Answers

I'm going to assume the following problem is what you meant.  Let me know if not.

(x²+x-12)/(x-3) * (x²-2x-3)/(x²+5x+4)

This is a question really testing your ability to factor the polynomials involved.  Once you do that it is fairly easy.  Here's what it looks like after factoring each of the polynomials:

[(x-3)(x+4)]/(x-3) * [(x-3)(x+1)]/[(x+4)(x+1)]

If you write this out on paper it is easier to see what to do.  In the first fraction you'll see that there's an (x-3) in the top and the bottom, so they cancel to 1, leaving only an (x+4) in the top.  The second fraction has an (x+1) in the top and bottom which also cancels to 1.  This leaves us with (x+4)(x-3) in the top of the new fraction and (x+4) in the bottom.  The two (x+4) factors cancel to 1 leaving you with the very simple final answer of (x-3).

Write it out on paper and it will be easier to follow what I've said here.  Hope that helps.

Charlie Gibson

Hi Jim,

Without parentheses this expression means that the addition is done last, therefore the first thing to do is to modify the form of each of the two fractions so they each have the same denominator (bottom number).  You do this by multiplying each fraction by some form of 1.  For the first fraction multiply it by 3/3 giving you 21/3a⁵.  For the second fraction multiply it by a⁴/a⁴ giving you 4a⁴/3a⁵.  Notice that we have now converted each fraction to a form with 3a⁵ in the denominator and yet we've not changed the value of either fraction.  We've only changed the form; just like 2/4 and 1/2 are two forms of the same fraction.  Once the denominators are the same, the addition is simple:

21/3a⁵ + 4a⁴/3a⁵ = (21+4a⁴)/3a⁵

I hope this is helpful.

Charlie Gibson

Hi Audrey,

Can you clarify the question you are asking?  I think I am missing something.  Sometimes teachers need their student's help too.  Can you help us understand your question better?

Charlie Gibson