pt <=> x(2x-7) - 2(2x-7)=0
<=>(x-2)(2x-7)=0
\(\left\{\begin{matrix}x-2=0\\2x-7=0\end{matrix}\right.\)\(\left\{\begin{matrix}x=2\\x=\frac{7}{2}\end{matrix}\right.\)
Vậy ....
\(x\left(2x-7\right)-4x+14=0\)
\(\Leftrightarrow x\left(2x-7\right)-\left(4x-14\right)=0\)
\(\Leftrightarrow x\left(2x-7\right)-2\left(2x-7\right)=0\)
\(\Leftrightarrow\left(2x-7\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[\begin{matrix}2x-7=0\\x-2=0\end{matrix}\right.\) \(\Leftrightarrow\left[\begin{matrix}x=\frac{7}{2}\\x=2\end{matrix}\right.\)
Vậy phương trình có tập nghiệm là \(S=\left\{\frac{7}{2};2\right\}\)
Có : \(x\left(2x-7\right)-4x+14=0\)
\(\Leftrightarrow\) \(x\left(2x-7\right)-2\left(2x-7\right)=0\)
\(\Leftrightarrow\) \(\left(2x-7\right)\left(x-2\right)=0\)
\(\Leftrightarrow\) \(\left[\begin{matrix}2x-7=0\\x-2=0\end{matrix}\right.\) \(\Leftrightarrow\) \(\left[\begin{matrix}2x=7\\x=2\end{matrix}\right.\) \(\Leftrightarrow\) \(\left[\begin{matrix}x=\frac{7}{2}\\x=2\end{matrix}\right.\)
Vậy tập nghiệm của phương trình \(S=\left\{\frac{7}{2};2\right\}\)
\(x\left(2x-7\right)-4x+14=0\\ x\left(2x-7\right)-2\left(2x-7\right)=0\\ =\left(2x-7\right)\left(x-2\right)=0\\ =\left\{\begin{matrix}2x-7=0\\x-2=0\end{matrix}\right.\Rightarrow\left\{\begin{matrix}2x=0+7\Rightarrow x=\frac{7}{2}\\x-2=0\Rightarrow x=2\end{matrix}\right.\)