+) ${\dfrac{2x}{5}+\dfrac{36}{6}=\dfrac{3x}{30}}$
⇔ ${ \dfrac{2x}{5}+6=\dfrac{x}{10}}$
⇔ ${ \dfrac{2.2x}{10}+\dfrac{60}{10}=\dfrac{x}{10}}$
⇔ ${ 2.2x+60=x}$
⇔ ${4x+60=x}$
⇔ ${ 4x-x=-60}$
⇔ ${ 3x=-60}$
⇔ ${ x=-20}$
+) ${ \dfrac{x}{24}+\dfrac{2x}{6}=\dfrac{x^2}{4}}$
⇔${\dfrac{x}{24}+\dfrac{4.2x}{24}=\dfrac{6.x^2}{24}}$
⇔ ${x+4.2x=6.x^2}$
⇔ ${ x+8x-6x^2=0}$
⇔ ${ 9x-6x^2=0}$
⇔ ${ 3x.(3-2x)=0}$
⇔ \(\left[ \begin{array}{l}3x=0\\3-2x=0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=0\\-2x=-3\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=0\\x=\dfrac{3}{2}\end{array} \right.\)
$\text{Vậy}$...
