Please help me factor the following:

81y^4-w^4y^4

Thanks in advance for your help.

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- Dec 16th 2009, 07:18 AMdkpeppardFactoring with exponents
Please help me factor the following:

81y^4-w^4y^4

Thanks in advance for your help.

- Dec 16th 2009, 07:37 AMStroodle
$\displaystyle 81y^4-w^4y^4$

$\displaystyle y^4(81-w^4)$

$\displaystyle y^4(9+w^2)(9-w^2)$

$\displaystyle y^4(9+w^2)(3+w)(3-w)$

$\displaystyle -y^4(w^2+9)(w+3)(w-3)$ - Dec 16th 2009, 07:38 AMdkpeppard
Stroodle, many thanks for your quick response and help!

- Dec 17th 2009, 06:30 AMdkpeppard
- Dec 17th 2009, 09:45 AMdkpeppard
Anyone else is welcome to jump in to and explain as well.

Thanks in advance. - Dec 17th 2009, 10:49 AMbigwave
$\displaystyle (81-w^4)$

this is a difference of squares

$\displaystyle

(9-w^2)(9+w^2)

$

if you FOIL this the middle terms will cancel out

$\displaystyle

81 + w^2 -w^2-w^4

$

leaving

$\displaystyle

81-w^4

$ - Dec 17th 2009, 10:53 AMdkpeppard