Hi again,

Have struggled with this for a while but getting nowhere.

$\displaystyle x^2=y^2-2yz-z^2$

I've reduced this to

$\displaystyle x^2=(y-z)^2-2z^2$

but can't seem to break it down any further in a similar method to my previous thread

http://www.mathhelpforum.com/math-he...tml#post674932

Any ideas would be greatly appreciated