hi,

i have been asked to factorise the following

$\displaystyle l^8-256$

using the difference of squares $\displaystyle a^2-b^2=(a+b)(a-b)$ and by working from the lowest term $\displaystyle (l^2-2^2)$, i managed to get a solution but its was more down to guesswork than a systematic attempt to solve this.

$\displaystyle (l^4+16)(l^2+4)(l+2)(l-2)$

is there a way of dealing with these type of questions?

thanks