\(x-\sqrt{2x+3}=0\) \(ĐK:x\ge\dfrac{-3}{2}\)
\(\Leftrightarrow x=\sqrt{2x+3}\left(x\ge0\right)\)
\(\Leftrightarrow x^2=2x+3\)
\(\Leftrightarrow x^2-2x-3=0\)
\(\Leftrightarrow\left(x-3\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\left(TM\right)\\x=-1\left(KTM\right)\end{matrix}\right.\)
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