Question

Giải phương trình x-\(\sqrt{x}\)-6=0

Answer 1

Ta có :

\(x-\sqrt{x}-6=0\)

\(\Leftrightarrow x+2\sqrt{x}-3\sqrt{x}-6=0\)

\(\Leftrightarrow\sqrt{x}\left(x+2\right)-3\left(\sqrt{x}+2\right)=0\)

\(\Leftrightarrow\left(\sqrt{x}+2\right)\left(\sqrt{x}-3\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x}+2=0\\\sqrt{x}-3=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x}=-2\left(loại\right)\\\sqrt{x}=3\end{matrix}\right.\) \(\Leftrightarrow x=9\)

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