Question

if x#y = x(x-y), what does x#(x#y) = ?

Answer 1

\[x\#(x\#y)=x\#\color{red}{(x(x-y))}\]
Think of this red part as your new "\(y\)" in \(x\#y\). Let's call it \(z\) to avoid confusion.

So you have \(x\#z=x(x-z)\). What do you get when you substitute back the expression for \(z\), \(z=x(x-y)\)?

Answer 2

I got it. So the next step would be x(x-(x^2-xy)). From there i can get it. Thank you for your help

Answer 3

Yes, you're welcome!