\(\left(x+5\right)\left(3x-7\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x+5=0\\3x-7=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-5\\x=\dfrac{7}{3}\end{matrix}\right.\)
\(\left(x+5\right)\left(3x-7\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x+5=0\\3x-7=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-5\\x=\dfrac{7}{3}\end{matrix}\right.\)
Vậy \(x\in\left\{-5;\dfrac{7}{3}\right\}\)
(x +5) (3x – 7)=0
\(=>\left[{}\begin{matrix}x+5=0\\3x-7=0\end{matrix}\right.=>\left[{}\begin{matrix}x=-5\\x=\dfrac{7}{3}\end{matrix}\right.\)
Vậy....
(x + 5)(3x - 7) = 0
⇔ x + 5 = 0 hoặc 3x - 7 = 0
⇔ x = 0 - 5 hoặc 3x = 7
⇔ x = -5 hoặc x = \(\dfrac{7}{3}\)
Vậy tập nghiệm S = { -5; \(\dfrac{7}{3}\)}
=> x + 5 = 0 hoặc 3x - 7 = 0
TH1:
x + 5 = 0
=> x = -5
TH2:
3x - 7 = 0
=> 3x = 7
=> x = 7/3
Vậy x = -5 hoặc x = 7/3