Question

giải phương trình

\(x-2\sqrt{x}=3\)

Answer 1

\(x^2-2\sqrt{x}=3\)

\(\Rightarrow\sqrt{x}\left(\sqrt{x}-2\right)=3\)

\(\Leftrightarrow\orbr{\begin{cases}\sqrt{x}=3\\\sqrt{x}-2=3\end{cases}}\)\(\Leftrightarrow\orbr{\begin{cases}x=9\\x=\frac{9}{4}\end{cases}}\)

Answer 2

\(x-2\sqrt{x}=3\)

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

\(\Leftrightarrow\orbr{\begin{cases}\sqrt{x}=3\\\sqrt{x}-2=3\end{cases}}\)\(\Leftrightarrow\orbr{\begin{cases}x=9\\x=\frac{9}{4}\end{cases}}\)

Answer 3

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

\(\left(\sqrt{x}+1\right)\left(\sqrt{x}-3\right)=0\)

\(\sqrt{x}-3=0\Leftrightarrow x=9\)