\(2x\left(x-5\right)-\left(x+3\right)^2=3x-x\left(5-x\right)\)
\(\Leftrightarrow2x^2-10x-x^2-3x-3x-9=3x-5x+x^2\)
\(\Leftrightarrow2x^2-x^2-x^2-10x-3x-3x-3x+5x=-9\)
\(\Leftrightarrow-14x=-9\)
\(\Leftrightarrow x=-\dfrac{9}{14}\)
Vậy phương trình có nghiệm là \(S=\left\{-\dfrac{9}{14}\right\}\)
\(2x\left(x-5\right)-\left(x+3\right)^2=3x-x\left(5-x\right)\)
\(\Leftrightarrow2x^2-10x-\left(x^2+6x+9\right)-3x-5x+x^2=0\)
\(\Leftrightarrow2x^2-10x-x^2-6x-9-3x-5x+x^2=0\)
\(\Leftrightarrow2x^2-24x=0\)
\(\Leftrightarrow2x\left(x-12\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}2x=0\\x-12=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=12\end{matrix}\right.\)
