\(2x^2-3x-5=0\)
\(\Leftrightarrow2x^2+2x-5x-5=0\)
\(\Leftrightarrow\left(x+1\right)\left(2x-5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+1=0\\2x-5=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=\frac{5}{2}\end{matrix}\right.\)
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b/ \(3x^2-7x+4=0\)
\(\Leftrightarrow3x^2-3x-4x+4=0\)
\(\Leftrightarrow\left(x-1\right)\left(3x-4\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\3x-4=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=\frac{4}{3}\end{matrix}\right.\)
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