BÀI LÀM ĐÂY NHÉ BẠN!!!
a) 2x + 3 = 0
⇔ 2x = -3
⇔ x = $\frac{-3}{2}$
b) 5x - 3( 3x - 6 ) = 0
⇔ 5x - 9x +18 = 0
⇔ -4x = -18
⇔ x = $\frac{9}{2}$
c) x² - 2x = 0
⇔ x( x - 2 ) = 0
⇔ \(\left[ \begin{array}{l}x=0\\x-2=0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=0\\x=2\end{array} \right.\)
d) 2x² + 5x = 0
⇔ x( 2x + 5 ) = 0
⇔ \(\left[ \begin{array}{l}x=0\\2x+5=0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=0\\x=\frac{-5}{2}\end{array} \right.\)
