a) 3x( x - 2 ) + 7( 2 - x ) =0
⇔ 3x( x - 2 ) - 7( x - 2 ) = 0
⇔ ( x - 2 )( 3x - 7 ) = 0
⇔ \(\left[ \begin{array}{l}x-2=0\\3x-7=0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=2\\x=\frac{7}{3} \end{array} \right.\)
b) 5(x + 2) - 3x^2 - 6x = 0
⇔ 5( x + 2 ) - 3x ( x + 2 ) = 0
⇔ ( x + 2 )( 5 - 3x ) = 0
⇔ \(\left[ \begin{array}{l}x+2=0\\5-3x=0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=-2\\x=\frac{5}{3} \end{array} \right.\)
~CHÚC BẠN HỌC TỐT~
