# How to simplify x^3 - y^3 / x - y

• Mar 10th 2012, 07:32 AM
AaPa
How to simplify x^3 - y^3 / x - y
How to simplify

x3 - y3 / x - y

• Mar 10th 2012, 07:42 AM
skeeter
Re: How to simplify x^3 - y^3 / x - y
Quote:

Originally Posted by AaPa
How to simplify

x3 - y3 / x - y

look up the factoring pattern for the difference of cubes in your text or online.
• Mar 10th 2012, 07:43 AM
Dobby
Re: How to simplify x^3 - y^3 / x - y
$\displaystyle \frac{((x-y)(x^2+xy+y^2))}{(x-y)}$
• Mar 10th 2012, 07:44 AM
Wilmer
Re: How to simplify x^3 - y^3 / x - y
You should know that:
x^3 - y^3 = (x - y)(x^2 + xy + y^2)
else you're not ready for this.

And your expression needs brackets: (x^3 - y^3) / (x - y)
• Mar 10th 2012, 08:16 AM
AaPa
Re: How to simplify x^3 - y^3 / x - y
I knew that x^3 - y^3 = (x - y)(x^2 + xy + y^2)

and

x^3 - y^3 / (x - y) = (x^2 + xy + y^2)

This is what I wanted to prove.
• Mar 10th 2012, 08:45 AM
Wilmer
Re: How to simplify x^3 - y^3 / x - y
Quote:

Originally Posted by AaPa
I knew that x^3 - y^3 = (x - y)(x^2 + xy + y^2)
and
x^3 - y^3 / (x - y) = (x^2 + xy + y^2)
This is what I wanted to prove.

Once more, be CAREFUL with brackets; should be:
(x^3 - y^3) / (x - y) = x^2 + xy + y^2

There is NOTHING to prove: simply cancel out the (x - y) terms: see Dobby's post...
• Mar 10th 2012, 10:12 PM
AaPa
Re: How to simplify x^3 - y^3 / x - y
Is there a way to find these factors of
x^3 - y^3
except try and error?
• Mar 10th 2012, 10:19 PM
Wilmer
Re: How to simplify x^3 - y^3 / x - y