a) $(3x-4)(2x+6)=0$
$⇔$ \(\left[ \begin{array}{l}3x-4=0\\2x+6=0\end{array} \right.\)
$⇔$ \(\left[ \begin{array}{l}x=4/3\\x=-3\end{array} \right.\)
b) $(5x-7)(2x-3)=0$
$⇔$ \(\left[ \begin{array}{l}5x-7=0\\2x-3=0\end{array} \right.\)
$⇔$ \(\left[ \begin{array}{l}x=7/5\\x=3/2\end{array} \right.\)
c) $(4x-8)(4+5x)=0$
$⇔$ \(\left[ \begin{array}{l}4x-8=0\\4+5x=0\end{array} \right.\)
$⇔$ \(\left[ \begin{array}{l}x=2\\x=-4/5\end{array} \right.\)
d) $(x-7)(3-4x)(2x+4)=0$
$⇔$ \(\left[ \begin{array}{l}x-7=0\\3-4x=0\\2x+4=0\end{array} \right.\)
$⇔$ \(\left[ \begin{array}{l}x=7\\x=3/4\\x=-2\end{array} \right.\)
e) $3x-6+x=9-x$
$⇔4x-6=9-x$
$⇔4x+x=9+6$
$⇔5x=15$
$⇔x=3$
