a) $2x^2-3x=0$
$⇔x.(2x-3)=0$
$⇔$\(\left[ \begin{array}{l}x=0\\2x-3=0\end{array} \right.\)
$⇔$\(\left[ \begin{array}{l}x=0\\2x=3\end{array} \right.\)
$⇔$\(\left[ \begin{array}{l}x=0\\x=\dfrac{3}{2}\end{array} \right.\)
b) $\dfrac{4+3x^2}{x-3}-\dfrac{2x+2x^2}{x-3}+\dfrac{2x-13}{x-3}=0$
$⇔\dfrac{4+3x^2-2x-2x^2+2x-13}{x-3}=0$
$⇔\dfrac{x^2-9}{x-3}=0$
$⇔\dfrac{(x-3)(x+3)}{x-3}=0$
$⇔x+3=0$
$⇔x=-3$