\(\Leftrightarrow-2x^2+6x-x+3=0\)
\(\Leftrightarrow-2x\left(x-3\right)-\left(x-3\right)=0\)
\(\Leftrightarrow\left(2x+1\right)\left(x-3\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=-\frac{1}{2}\\x=3\end{matrix}\right.\)
\(-2x^2+5x+3=0\)
\(\Leftrightarrow-2x^2+6x-x+3=0\)
\(\Leftrightarrow\left(-2x^2+6x\right)-\left(x-3\right)=0\)
\(\Leftrightarrow-2x.\left(x-3\right)-\left(x-3\right)=0\)
\(\Leftrightarrow\left(x-3\right).\left(-2x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\-2x-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\-2x=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\frac{1}{2}\end{matrix}\right.\)
Vậy phương trình có tập hợp nghiệm là: \(S=\left\{3;-\frac{1}{2}\right\}.\)
Chúc bạn học tốt!
