\ANG{Faktorisiere soweit wie m"oglich:
\begin{enumerate}
\item
$9a^2x-9a^2y-12abx+12aby+4b^2y-4b^2x$
\item
$\frac19a^2x^2-\frac16a^2xy+\frac14a^2y^2-\frac19b^2x^2+\frac16b^2xy-\frac14b^2y^2 $
\end{enumerate}}

\LSG{
(a) $(9a^2-12ab-4b^2)(x-y)$\qquad (b) $(a-b)(a+b)(\frac19x^2-\frac16xy+\frac14y^2)$}


