Mng giúp e câu 2 vs ạ, e cảm ơn

$\text{Câu 2: }$

$\text{a) 5x - 20 = 0 }$

$\text{⇔ 5x = 20 }$

$\text{⇔ x = 4 }$

$\text{b) x² - 9 = 0 }$

$\text{⇔ ( x + 3 )( x - 3 ) = 0 }$

⇔ $\left[\begin{matrix} x + 3 = 0 \\ x - 3 = 0\end{matrix}\right.$⇔$\left[\begin{matrix} x = -3\\ x = 3 \end{matrix}\right.$

$\text{c) 5x² - 3x = 0 }$

$\text{⇔ x( 5x - 3 ) = 0 }$

⇔ $\left[\begin{matrix} x = 0 \\ x = \dfrac{3}{5} \end{matrix}\right.$

$\text{d) 5( x + 2 ) - 3x - 6 = 0 }$

$\text{⇔ 5( x + 2 ) - 3( x + 2 ) = 0 }$

$\text{⇔ 2( x + 2 ) = 0 }$

$\text{⇔ 2x + 4 = 0 }$

$\text{⇔ 2x = -4 }$

$\text{⇔ x = -2 }$

$\text{e) ( 2x - 1 )² = ( x + 3 )² }$

$\text{⇔ ( 2x - 1 )² - ( x + 3 )² = 0 }$

$\text{⇔ ( 2x - 1 + x + 3 )( 2x - 1 - x - 3 ) = 0 }$

$\text{⇔ ( 3x + 2 )( x - 4 ) = 0 }$

⇔ $\left[\begin{matrix} 3x + 2 = 0 \\ x - 4 = 0 \end{matrix}\right.$ ⇔ $\left[\begin{matrix} x = \dfrac{-2}{3} \\ x = 4 \end{matrix}\right.$