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#1 2005-07-07 11:53:51

Kandai
Guest

Algebra

I know how to get from here:

-2(w-5)(w+5)(w^2+25)

to here:

-2w^4+1250

But I don't know how to get from here:

-2w^4+1250

to here:

-2(w-5)(w+5)(w^2+25)


The same with this problem:
a^9-1
(a-1)(a^2+a+1)(a^6+a^3+1)

#2 2005-07-07 17:27:03

Jai Ganesh
Administrator
Registered: 2005-06-28
Posts: 45,956

Re: Algebra

Its always difficult to find the factors, given the simplest form.
a^3 - b^3 is (a-b)(a^2 + ab + b^2).
If one of the factors is known, it becomes a bit easier.
For lower degrees, by remembering some formulae, it can be done easily.
Like a^2 - b^2 = (a+b) x (a-b),
(a^3 + b^3) = (a+b) x (a^2 - ab + b^2) etc.
When you are aksed to prove that the LHS is equal to the RHS,
it is always better to start with lower degrees.


It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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