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.]]>

-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)