6ax2+4ax-9x-6 = 0
<=> ( 6ax2+4ax ) - ( 9x+6 ) = 0
<=> 2ax(3x+2) - 3(3x+2) = 0
<=> ( 2ax-3 )( 3x+2 ) = 0
<=> \(\left[{}\begin{matrix}2ax-3=0\\3x+2=0\end{matrix}\right.\)
<=> \(\left[{}\begin{matrix}2ax=3\\3x=-2\end{matrix}\right.\)
<=> \(\left[{}\begin{matrix}x=\frac{3}{2a}\\x=\frac{-2}{3}\end{matrix}\right.\)