\(\left(3x-2\right)\left(4x+5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}3x-2=0\\4x+5=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=-\dfrac{4}{5}\end{matrix}\right.\)
Vậ pt có tập nghiệm `S={2/3 ; -4/5}`
` ( 3x - 2).(4x+5) = 0`
\(=>\left[{}\begin{matrix}3x-2=0\\4x+5=0\end{matrix}\right.\)
\(=>\left[{}\begin{matrix}3x=2\\4x=-5\end{matrix}\right.\)
\(=>\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=-\dfrac{5}{4}\end{matrix}\right.\)
Vậy...
\(\Leftrightarrow\left[{}\begin{matrix}3x-2=0\\4x+5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=-\dfrac{5}{4}\end{matrix}\right.\)
