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aizak23
Jul 26, 2008, 11:34 AM
I really need help with this problem and I know it is easy but I forgot how to factor completely 125 -27z^3. please help me!!

galactus
Jul 26, 2008, 11:42 AM
Note the difference of two cubes

aizak23
Jul 26, 2008, 11:47 AM
Yea I remember now!
Is this the answer? Jajaja
Just to be sure!
(5-3)(25+15w+9w)

galactus
Jul 26, 2008, 12:04 PM
No, not quite.

(5)^{3}-(3z)^{3}

Now use the formula (x-y)(x^{2}+xy+y^{2})

Where x=5, \;\ y=3z

aizak23
Jul 26, 2008, 12:09 PM
Yea!
I wrote it wrong
It is (5-3z)(25+15z+9z)
I couldn't remember that
But the class is over now
Thanks!

m4inguyen
Jan 27, 2011, 08:53 PM
you still got wrong
it is (5-3z)(25+15z+9Z^2)