$${{\mathtt{e}}}^{{\mathtt{\,-\,}}{\mathtt{x}}}{\mathtt{\,-\,}}\left({\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{1}}\right){\mathtt{\,\times\,}}{{\mathtt{e}}}^{{\mathtt{\,-\,}}{\mathtt{x}}} = \left({{\mathtt{e}}}^{{\mathtt{\,-\,}}{\mathtt{x}}}\right){\mathtt{\,\times\,}}\left({\mathtt{2}}{\mathtt{\,-\,}}{\mathtt{x}}\right)$$
Sorry, ich hatte ein Minus vergessen: $${{\mathtt{e}}}^{{\mathtt{\,-\,}}{\mathtt{x}}}$$ hinter der Klammer !!
So dürfte es aber stimmen !