http://img5.imageshack.us/img5/9369/letssee.png

I know i mess up somewhere on the signs.

(Headbang)

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- Mar 22nd 2009, 04:26 PMKenlen83Answer Check for this problem.
http://img5.imageshack.us/img5/9369/letssee.png

I know i mess up somewhere on the signs.

(Headbang) - Mar 22nd 2009, 10:21 PMADARSH
- Mar 23rd 2009, 05:11 AMstapel
There's a mnemonic for keeping track of the signs. The

**factoring formulas**are:

. . . . .$\displaystyle \left(a^3\, -\, b^3\right)\, =\, (a\, -\, b)\left(a^2\, +\, ab\, +\, b^2\right)$

. . . . .$\displaystyle \left(a^3\, +\, b^3\right)\, =\, (a\, +\, b)(\left(a^2\, -\, ab\, +\, b^2\right)$

You've noticed that the terms inside the formula are always the same; it's only the signs that differ. Use "SOAP" to keep track of the signs:

Take the sign of the sum or difference of cubes that you're needing to factor. Then look at the two parentheses that you need to fill in:

. . . . .$\displaystyle (a\, \mbox{ S }\, b)\left(a^2\, \mbox{ O }\, ab\, \mbox{ AP }\, b^2\right)$

The letters stand for "the**S**ame sign as what you're factoring", "the**O**pposite sign from what you're factoring", and "**A**lways use a**P**lus sign here".

(Wink)